"The Phone is my Lifeline": Use of Mobile Phone Technology to Support Recovery among Individuals in Treatment for Substance Use Disorders.

Background: People experiencing substance use disorders (SUD) face myriad challenges in maintaining changes in substance use after treatment. Mobile phones can play a role in supporting the recovery process. To date, research has not explored how individuals use mobile phones to seek social support as they enter SUD recovery. Objectives: We sought to understand how individuals in SUD treatment use mobile technology in support of their recovery. Methods: We conducted semi-structured interviews with thirty individuals in treatment for any SUD in northeastern Georgia and southcentral Connecticut. Interviews explored participants' attitudes toward mobile technology and how they used mobile technology while using substances, in treatment, and in recovery. Qualitative data were coded and analyzed using thematic analysis. Results: We identified three major themes related to how participants: (1) adapted their use of mobile technology as they entered recovery, (2) relied on mobile technology for social support while in recovery, while (3) some found aspects of mobile technology triggering. Many individuals in SUD treatment reported using mobile phones to buy or sell drugs; as such, they took measures to adapt their use of mobile technology as they changed substance use behaviors. As they entered recovery, individuals relied on mobile phones for affiliational, emotional, informational, and instrumental support, though some did share they found some aspects of mobile phones triggering. Conclusion: These findings highlight the importance of treatment providers engaging in conversations around mobile phone use to help individuals avoid triggers and connect with social supports. These findings uncover new opportunities for recovery support interventions utilizing mobile phones as a delivery mechanism.

The use of multiple hypothesis-generating methods in an outbreak investigation of Escherichia coli O121 infections associated with wheat flour, Canada 2016-2017.

A Canadian outbreak investigation into a cluster of Escherichia coli O121 was initiated in late 2016. When initial interviews using a closed-ended hypothesis-generating questionnaire did not point to a common source, cases were centrally re-interviewed using an open-ended approach. The open-ended interviews led cases to describe exposures with greater specificity, as well as food preparation activities. Data collected supported hypothesis generation, particularly with respect to flour exposures. In March 2017, an open sample of Brand X flour from a case home, and a closed sample collected at retail of the same brand and production date, tested positive for the outbreak strain of E. coli O121. In total, 76% (16/21) of cases reported that they used or probably used Brand X flour or that it was used or probably was used in the home during their exposure period. Crucial hypothesis-generating techniques used during the course of the investigation included a centralised open-ended interviewing approach and product sampling from case homes. This was the first outbreak investigation in Canada to identify flour as the source of infection.

An outbreak of hepatitis A in Canada: The use of a control bank to conduct a case-control study.

An outbreak of 18 cases of hepatitis A virus infection across five Canadian provinces was investigated. Case onsets occurred between October 2017 and May 2018. A retrospective matched case-control study was conducted to identify the likely source of the outbreak. Three matched controls were recruited for each case using a previously established control bank, supplemented by landline and cell phone call lists. Univariate and multivariate matched analyses were conducted to identify a potential outbreak source. Seventy-two per cent of controls were recruited through the control bank, and required on average 25.5 calls per recruited control; 20% of controls were recruited through a landline sample and 8% of controls were recruited through a cell phone sample, requiring an average of 847.3 and 331.7 calls per recruited control, respectively. Results of the analysis pointed to shrimp/prawns (odds ratio (OR) 15.75, p = 0.01) and blackberries (OR 7.21, p = 0.02) as foods of interest, however, an outbreak source could not be confirmed. The control bank proved to be a more efficient method for control recruitment than random call lists. Expanding the control bank size and using alternative methods, such as online surveys, may prove beneficial for increasing the timeliness of a case-control study during an outbreak investigation.

Methods for generating hypotheses in human enteric illness outbreak investigations: a scoping review of the evidence.

Enteric illness outbreaks are complex events, therefore, outbreak investigators use many different hypothesis generation methods depending on the situation. This scoping review was conducted to describe methods used to generate a hypothesis during enteric illness outbreak investigations. The search included five databases and grey literature for articles published between 1 January 2000 and 2 May 2015. Relevance screening and article characterisation were conducted by two independent reviewers using pretested forms. There were 903 outbreaks that described hypothesis generation methods and 33 papers which focused on the evaluation of hypothesis generation methods. Common hypothesis generation methods described are analytic studies (64.8%), descriptive epidemiology (33.7%), food or environmental sampling (32.8%) and facility inspections (27.9%). The least common methods included the use of a single interviewer (0.4%) and investigation of outliers (0.4%). Most studies reported using two or more methods to generate hypotheses (81.2%), with 29.2% of studies reporting using four or more. The use of multiple different hypothesis generation methods both within and between outbreaks highlights the complexity of enteric illness outbreak investigations. Future research should examine the effectiveness of each method and the contexts for which each is most effective in efficiently leading to source identification.

Kidney allograft survival of African American and Caucasian American recipients with lupus.

BACKGROUND: African Americans with lupus who receive kidney transplants have high prevalence of predictors of allograft failure, which can explain their poor outcomes. METHODS: Of 1223 African Americans and 1029 Caucasian Americans with lupus who received kidney transplants from deceased donors between 1987 and 2006 with complete records in the UNOS program, 741 pairs were matched in 16 predictors employing a predicted probability of group membership. The primary outcome was allograft failure. Main secondary outcomes were rejection, allograft failure due to rejection, and mortality. RESULTS: Matched pairs were predominantly women (82%) with a mean age of 39 years. Twenty-four percent of recipients received kidneys from expanded criteria donors. African Americans and Caucasian Americans matched well (p ≥ 0.05): donor age, gender and race; recipient age, gender, education and insurance; dialysis prior to transplant, kidneys from expanded criteria donors, cold ischemia time, history of prior kidney transplant, panel reactive antibodies, human leukocyte antigens mismatch, blood type compatibility, transplant Era, and follow-up time. Contrary to the unmatched cohort with significantly higher allograft failure rate (events per 100 patient-years) in African Americans compared to Caucasian Americans (10.49 vs 6.18, p<0.001), matched pairs had similar allograft failure rates (8.41 vs 7.81, p=0.418). Matched pairs also had similar rates of rejections (9.82 vs 9.39, p=0.602), allograft failure due to rejection (6.19 vs 5.71, p=0.453), and mortality (2.79 vs 3.52, p=0.097). CONCLUSION: In lupus recipients of kidney transplants from deceased donors, African American and Caucasian Americans have similar allograft failure rates when predictors are matched between groups.

Development of a Multi-Level Family Planning Intervention for Couples in Rural Uganda: Key Findings & Adaptations Made from Community Engaged Research Methods.

Background: Uganda has among the highest fertility rates in the world and multi-level barriers contribute to the low contraceptive use. Objective: The objective of this study was to develop a culturally and socially relevant, community-based intervention to increase contraceptive use among couples in rural Uganda through community-engaged research methods. This study reports on the community-engaged research that informed the intervention's content and structure and the final content of the intervention; the evaluation of the pilot intervention will be reported upon completion. Methods: An intervention steering committee of community stakeholders reviewed the initially proposed intervention content and approach. Focus groups were conducted with men and women separately (N=26) who had unmet need for family planning. Fifteen key-informant interviews were conducted with community leaders and family planning stakeholders. Finally, the 4-session intervention was pilot tested with a cohort of couples (N=7) similar in demographics to the target sample of the future pilot intervention trial. Qualitative data were analyzed thematically. Results: Findings included the identification of community beliefs to reshape to increase family planning acceptance, as well as strategies to engage men, acceptable approaches for community leader involvement in the intervention to endorse family planning, and methods for managing gender dynamics and minimizing risk of unintended negative consequences of participation. The findings were used to shape the ideal structure and format of the intervention, including the distribution of contraceptives directly during group sessions, and identified the need to strengthen health worker capacity to provide Long-Acting Reversable Contraceptives (LARCs) as part of the intervention. Conclusions: These findings were used to refine an intervention before a larger scale pilot test of its feasibility, acceptability, and potential efficacy. They can inform other multi-level family planning interventions in similar settings and the methods can be adopted by others to increase the feasibility, acceptability, and cultural relevance of interventions.

Protocol for the pilot quasi-experimental controlled trial of a gender-responsive implementation strategy with providers to improve HIV outcomes in Uganda.

BACKGROUND: Antiretroviral treatment (ART) is the most effective clinical intervention for reducing morbidity and mortality among persons living with HIV. However, in Uganda, there are disparities between men and women in viral load suppression and related HIV care engagement outcomes, which suggests problems with the implementation of ART. Gender norms are a known driver of HIV disparities in sub-Saharan Africa, and patient-provider relationships are a key factor in HIV care engagement; therefore, the role of gender norms is important to consider in interventions to achieve the equitable provision of treatment and the quality of ART counseling. METHODS: The overall research objective of this study is to pilot test an implementation strategy (i.e., methods to improve the implementation of an evidence-based intervention) to increase providers' capacity to provide gender-responsive treatment and counseling to men and women on HIV treatment in Uganda. Delivered to HIV providers, this group training adapts evidence-based strategies to reduce gender biases and increase skills to deliver gender-specific and transformative HIV counseling to patients. The implementation strategy will be piloted through a quasi-experimental controlled trial. Clinics will be randomly assigned to either the intervention or control conditions. The trial will assess feasibility and acceptability and explore barriers and facilitators to implementation and future adoption while gathering preliminary evidence on the implementation strategy's effectiveness by comparing changes in patient (N = 240) and provider (N = 80-140) outcomes across intervention and control clinics through 12-month follow-up. Quantitative data will be descriptively analyzed, qualitative data will be analyzed through thematic analysis, and these data will be mixed during the presentation and interpretation of results where appropriate. DISCUSSION: This pilot intervention trial will gather preliminary evidence on the acceptability, feasibility, and potential effect of a novel implementation strategy to improve men and women's HIV care engagement, with the potential to reduce gender disparities in HIV outcomes. TRIAL REGISTRATION: Clinicaltrials.gov NCT05178979 , retrospectively registered on January 5, 2022.

A review of the impact of blue space on the urban microclimate.

The urban heat island (UHI) phenomenon represents a major public health issue and has received great attention due to rapid urbanisation. Blue spaces have long been considered a possible mitigation strategy to ameliorate the UHI. However, our knowledge regarding the interaction of waterbodies with their urban surroundings is still limited. This review attempts through a comparative analysis of the available literature to examine the thermal effects of static blue spaces on the urban climate. Remote sensing studies are the most common approach analysed in this review but there is a clear disparity between the cooling potentials reported by remote sensing as opposed to field measurements or numerical simulations, likely due to a lack of nocturnal measurements, when warming due to thermal inertia can occur and consideration of the latent heat flux. The size and shape of blue spaces are shown to be important variables for the cooling achieved in urban settings but there is no consensus in the literature. This is likely due to the different locations and climates of the studies, it can be hypothesised that in locations with an even distribution of wind directions a rounder waterbody is more effective while in locations where wind direction is more uniform an elongated waterbody aligned to the wind is more effective due to the increased fetch. From the analysis of the literature, it is clear that there is still a distinct knowledge gap regarding the physical interpretation of waterbodies' contribution to the urban climate. There is also a current lack of information about the diurnal and seasonal variability of the various structures and processes. There is evidence, however, that the comfort achieved by sensible cooling can be offset by the increased water vapour content and that during the night blue spaces may actually exacerbate the UHI, reducing urban thermal comfort.

Predictors of HIV/AIDS confirmation and differences by guardian status in HIV+ adolescents in Jamaica.

BACKGROUND: Approximately 25% of the cumulative AIDS cases in Jamaica involve adolescents and young adults. However the lives of adolescents living with HIV within Jamaica and the Caribbean have been understudied. OBJECTIVES: (1) To describe the sociodemographic characteristics of HIV+ Jamaican adolescents who have ever been a part of the Kingston Paediatric/Perinatal HIV Programme (KPAIDS) from September 1, 2002 to August 31, 2006 (2). To identify predictors of HIV/AIDS confirmation as well as factors associated or uniquely present in these adolescents by their guardian status. METHODS: Seventy-two HIV+ adolescents, ages 10-19 years, were included. Factors studied included demographics as well as time to and time between HIV and AIDS confirmation. Data were analyzed by bivariate and multivariate statistics. RESULTS: The mean age of the adolescents was 12.6 +/- 2.8 years with slightly more males (52.8%) in the programme. There were equal proportions of adolescents living with HIV as with AIDS (43.1%). There were equal proportions who were lost to follow-up or deceased (8.3%). Twenty-two of them lived with parents, 25 with guardians and 18 in residential institutions. The primary mode of transmission was perinatal infection (68.1%), followed by sexual (20.8%), blood transfusion (2.9%) and unknown (8.3%). The mean time from HIV exposure to HIV confirmation and AIDS confirmation in mother-to-child transmission (MTCT) cases were 8.0 +/- 2.9 years and 9.6 +/- 3.3 years, respectively. In the multivariate analysis model, age and gender were significant in predicting time from HIV exposure to HIV confirmation. CONCLUSION: The majority of HIV-positive adolescents reside with parents and guardians and this might indicate support in spite of stigma and discrimination. However; the mean time to HIV confirmation in MTCT cases is quite long and must be reduced.

Utilising green and bluespace to mitigate urban heat island intensity.

It has long been recognised that cities exhibit their own microclimate and are typically warmer than the surrounding rural areas. This 'mesoscale' influence is known as the urban heat island (UHI) effect and results largely from modification of surface properties leading to greater absorption of solar radiation, reduced convective cooling and lower water evaporation rates. Cities typically contain less vegetation and bodies of water than rural areas, and existing green and bluespace is often under threat from increasing population densities. This paper presents a meta-analysis of the key ways in which green and bluespace affect both urban canopy- and boundary-layer temperatures, examined from the perspectives of city-planning, urban climatology and climate science. The analysis suggests that the evapotranspiration-based cooling influence of both green and bluespace is primarily relevant for urban canopy-layer conditions, and that tree-dominated greenspace offers the greatest heat stress relief when it is most needed. However, the magnitude and transport of cooling experienced depends on size, spread, and geometry of greenspaces, with some solitary large parks found to offer minimal boundary-layer cooling. Contribution to cooling at the scale of the urban boundary-layer climate is attributed mainly to greenspace increasing surface roughness and thereby improving convection efficiency rather than evaporation. Although bluespace cooling and transport during the day can be substantial, nocturnal warming is highlighted as likely when conditions are most oppressive. However, when both features are employed together they can offer many synergistic ecosystem benefits including cooling. The ways in which green and bluespace infrastructure is applied in future urban growth strategies, particularly in countries expected to experience rapid urbanisation, warrants greater consideration in urban planning policy to mitigate the adverse effects of the UHI and enhance climate resilience.

Prenatal Depressive Symptoms and Postpartum Sexual Risk Among Young Urban Women of Color.

STUDY OBJECTIVE: To determine whether prenatal depressive symptoms are associated with postpartum sexual risk among young, urban women of color. DESIGN: Participants completed surveys during their second trimester of pregnancy and at 1 year postpartum. Depressive symptoms were measured using the Center for Epidemiologic Studies-Depression Scale, excluding somatic items because women were pregnant. Logistic and linear regression models adjusted for known predictors of sexual risk and baseline outcome variables were used to assess whether prenatal depressive symptoms make an independent contribution to sexual risk over time. SETTING: Fourteen community health centers and hospitals in New York City. PARTICIPANTS: The participants included 757 predominantly black and Latina (91%, n = 692) pregnant teens and young women aged 14-21 years. INTERVENTIONS AND MAIN OUTCOME MEASURES: The main outcome measures were number of sex partners, condom use, exposure to high-risk sex partners, diagnosis of a sexually transmitted disease, and repeat pregnancy. RESULTS: High levels of prenatal depressive symptoms were significantly associated with increased number of sex partners (ß = 0.17; standard error, 0.08), decreased condom use (ß = -7.16; standard error, 3.08), and greater likelihood of having had sex with a high-risk partner (odds ratio = 1.84; 95% confidence interval, 1.26-2.70), and repeat pregnancy (odds ratio = 1.72; 95% confidence interval, 1.09-2.72), among participants who were sexually active (all P < .05). Prenatal depressive symptoms were not associated with whether participants engaged in postpartum sexual activity or sexually transmitted disease incidence. CONCLUSION: Screening and treatment for depression should be available routinely to women at risk for antenatal depression.

Effects of cholinergic-rich neural grafts on radial maze performance of rats after excitotoxic lesions of the forebrain cholinergic projection system--I. Amelioration of cognitive deficits by transplants into cortex and hippocampus but not into basal forebrain.

After ibotenate (10.0 mg/ml) lesions to the nucleus basalis and medial septal regions, at the source of the cortical and hippocampal branches of the forebrain cholinergic projection system, rats displayed long-lasting stable impairment in reference and working memory in both spatial (place) and associative (cue) radial maze tasks. Cell suspension transplants of cholinergic-rich fetal basal forebrain tissue dissected at embryonic day 15 substantially improved all aspects of radial maze performance to a comparable degree whether sited in cortex, hippocampus, or both regions of the host brain. No additive effects were obtained with grafts in both terminal regions, but total graft volume, assessed stereologically, showed a significant negative correlation with error scores. Rats with behaviourally effective grafts, like controls, were disrupted in the place task when tested in dim light which obscured extra-maze spatial cues. Lesioned rats were not affected by change in lighting. Grafts of cholinergic-poor fetal hippocampal tissue did not improve radial maze performance; neither did grafts of cholinergic-rich tissue placed within the host basal forebrain lesion sites. In rats with cholinergic-rich terminal grafts, cortical and hippocampal choline acetyltransferase activity was restored to control level, commensurate with site of transplant, whereas it was significantly reduced in lesioned animals and those with functionally ineffective grafts. The indiscriminate error pattern and insensitivity to changes in lighting shown by lesioned rats suggested that lesioning primarily disrupted attention rather than short- or long-term spatial or associative memory processes. Since rats with cholinergic-rich grafts showed both reduced errors and recovery of stimulus control, the data indicated that grafts affected information processing, rather than changes in motor or motivational processes. Changes in choline acetyltransferase activity and the behavioural efficacy of cholinergic-rich grafts are consistent with the involvement of acetylcholine in the behavioural deficits and recovery displayed by lesioned and grafted groups, but do not rule out contributions from other factors. The equipotency of grafts within each terminal region suggests also that there may be a considerable degree of functional cooperation between the two branches of the forebrain cholinergic projection system. Functional recovery may involve local, nonspecific synaptic or paracrine mechanisms within the target regions, since grafts were efficacious only when placed in the terminal areas, but not when sited homotopically in the basal forebrain, indicating that they did not achieve any functionally significant structural repair to the host brain at that site.

Astrocyte transplants alleviate lesion induced memory deficits independently of cholinergic recovery.

Basal forebrain tissue fragments taken from embryonic day 15 were separated into primary astrocytes and primary neurons in culture and grafted to rats with alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid lesions to the nucleus basalis and medial septal regions. The two cell types were compared in two experimental paradigms for their behavioural, biochemical and histochemical effects; standard transplants of whole basal forebrain and sham transplants served as positive and negative controls, respectively. Each transplant cell type was characterised by in vitro immunocytochemistry to assess content and purity. Memory deficits produced by the lesions in a spatial win-stay T-maze task (Experiment 1) and a spatial plus associative radial maze task (Experiment 2) were significantly improved by the astrocyte, but not by the neuronal, primary cell transplants. The astrocyte graft groups performed as well as standard cholinergic rich basal forebrain groups, reaching control levels on both tasks, while the neuronal transplant groups were not significantly different to lesioned (sham transplanted) rats. There was no recovery in choline acetyltransferase activity in brain regions containing astrocyte grafts whereas activity in the neuronal graft regions was increased (often to control levels), similar to recovery produced by basal forebrain grafts. Grafts in all groups survived, transplanted neurons displaying similar morphology and placement in the host brain to unseparated basal forebrain grafts, while astrocytes showed evidence of migration. The cultured astrocytes were estimated to be > 95% pure, showing positive staining for all astrocyte markers and an absence of staining for neuronal markers. The results indicate that the restoration of cognitive function following fetal grafting is not dependent upon a restoration of cholinergic neuronal activity but is more likely mediated via diffuse graft-host communication, with trophic secretion a probable factor. This study emphasizes the usefulness of astrocytes in the repair of central nervous system injury and has implications for therapeutic potential.

Contrasting effects of fetal CA1 and CA3 hippocampal grafts on deficits in spatial learning and working memory induced by global cerebral ischaemia in rats.

Functional effects of fetal hippocampal field grafts were assessed in rats with spatial learning and memory impairments following global cerebral ischaemia. Experiment 1 examined effects of grafts dissected from fields CA1 and CA3 at embryonic day 19 and from the dentate gyrus at postnatal day 1. Cell suspensions (15,000 cells/site) were implanted bilaterally at two points above the dorsal CA1 area two weeks after four-vessel occlusion (electrocoagulation of the vertebral arteries followed the 24 h later by occlusion of the carotid arteries for 15 min). Histological examination showed that CA1 neuronal loss (60-70%) was equivalent in all ischaemic groups and that 80% of CA1 and 60% of CA3 grafts survived and were sited appropriately in the alveus or corpus callosum above the area of ischaemic CA1 damage in the host, but there was no survival of dentate grafts. Results from rats with poor pyramidal cell graft survival were excluded, but those from rats with non-surviving dentate grafts were retained as an additional control group. Acquisition in the water maze was examined nine and 25 weeks after transplantation, and spatial working memory was assessed in three-door runway and water maze matching-to-position tasks 19 and 28 weeks after grafting, respectively. For water maze acquisition rats were trained with two trails/day and a 10 min inter-trial interval for 10-12 days to locate a submerged platform. Ischaemic rats with CA1 grafts learned the platform position as rapidly as non-ischaemic controls, searched appropriately in the training quadrant and were accurate in heading towards the platform, but were initially impaired on recall of the precise platform position on probe trials with the platform removed. Performance of ischaemic controls and groups with CA3 and non-surviving dentate graft groups was significantly impaired relative to controls and to the CA1 grafted group. The CA1 grafted group was also as successful as controls in matching-to-position in the water maze and substantially superior to the other ischaemic groups, assessed using three trials/day, with a 30-s inter-trial interval and a different platform position on each day. In a more complex matching-to-position task in the three-door runway, the performance of the CA1 grafted group was significantly impaired relative to controls, although superior to that of the other ischaemic control and graft groups. Functional recovery with CA1, but not CA3, grafts in ischaemic rats was replicated in a second experiment which assessed water maze acquisition and working memory at 10 and 14 weeks after transplantation, in rats with 90% graft survival. These results indicate that long-lasting, task-dependent improvements can be seen in ischaemic rats with CA1 fetal grafts in both aversively and appetitively motivated spatial learning tasks. The findings suggest that functional recovery requires homotypic replacement of CA1 cells damaged by ischaemia, rather than provision of structurally similar glutamate-releasing CA3 pyramidal cells.

Recovery of spatial learning by grafts of a conditionally immortalized hippocampal neuroepithelial cell line into the ischaemia-lesioned hippocampus.

Transient global cerebral ischaemia in rats causes relatively circumscribed and specific damage to the CA1 pyramidal cells of the dorsal hippocampus, along with a cognitive deficit manifest as difficulties in the performance of a range of spatial learning and memory tasks. Our previous studies have shown that restoration of behavioural performance in ischaemic rats by neural grafts taken relatively late in fetal development occurs only after local replacement of cells homotypic to those lost through the ischaemic insult. This lesion-plus-behaviour model therefore offers a powerful means for establishing whether multipotent embryonic neuroepithelial cells will engraft the damaged CA1, develop into appropriate neuronal phenotypes and produce behavioural recovery. Here we report that, in rats subjected to 15 min of global cerebral ischaemia, intrahippocampal implants of a conditionally immortal, multipotent cell line, directly derived from the embryonic day 14 hippocampal neuroepithelium of the H-2Kb-tsA58 transgenic mouse, selectively repopulated the lesioned CA1 pyramidal layer and restored ischaemia-induced deficits in acquisition of a hidden platform location in the Morris water maze.

Effects of fetal hippocampal field grafts on ischaemic-induced deficits in spatial navigation in the water maze.

Transitory global cerebral ischaemia induced in rats by four vessel occlusion for 15 min produced substantial loss of CA1 cells in dorsal hippocampus, and minimal damage in other intra- and extrahippocampal forebrain regions examined. Ischaemic rats showed long-lasting deficits in spatial navigation in the water-maze, consisting of impaired learning to locate a hidden platform in a novel pool, a substantial increase in time spent searching close to the platform without finding it, and moderate deficits in matching to position in a working memory task. Groups of ischaemic rats were implanted with fetal tissue dissected from hippocampal CA1 field, containing glutamatergic CA1 pyramidal cells, from dentate gyrus, containing glutamatergic dentate granule cells, and from basal forebrain, containing cholinergic cells, with grafts sited in the alveus above the damaged CA1 region, for comparison with non-grafted ischaemic and non-ischaemic control groups, over a series of tests from four to 20 weeks after grafting. All ischaemic groups showed comparable acquisition deficits prior to transplantation, and similar loss of CA1 cells on post mortem examination. When tested in a familiar pool in retention and reversal learning of the original platform position, and a working memory task, all ischaemic rats performed better than in initial acquisition. However, rats receiving CA1 grafts showed the most consistent improvement relative to ischaemic controls. When tested in a second (i.e. novel) pool, ischaemic rats again showed marked impairment, whereas rats with CA1 grafts were significantly superior, and learned as rapidly as non-ischaemic controls. The performance of groups with dentate granule and basal forebrain grafts was similar to that of the non-grafted ischaemic control group throughout testing. These results suggest that ischaemic rats are impaired in the adaptive use of spatial information, as shown by acquisition and working memory deficits, but not in long- or short-term memory storage processes, and are also impaired in precise spatial localization. The effects of CA1 grafts in restoring spatial abilities, shown most clearly when rats were tested in a novel environment, suggest that these grafts may have assisted with repair to the damaged host circuit, rather than acted through the release of an appropriate neurotransmitter, since the glutamatergic dentate granule grafts were ineffective. However, CA1 grafts showed better survival and growth than the other types of transplant, so that functional recovery may have been related to graft viability rather than to the specific type of graft.

Functional reconstruction of the hippocampus: fetal versus conditionally immortal neuroepithelial stem cell grafts.

Late fetal CA1 hippocampal grafts and stem cell grafts from the conditionally immortal MHP36 clonal line derived from the H-2Kb-tsA58 transgenic mouse neuroepithelium both improved spatial deficits in rats with ischaemic CA1 damage induced by four-vessel occlusion (4VO). However, the distribution of fetal and MHP36 grafts differed. Fetal cells lodged in clumps around the implant sites and along the corpus callosum, whilst MHP36 grafts infiltrated the area of CA1 ischaemic damage, achieving apparent architectural reconstruction of the hippocampus. The migration of MHP36 cells is damage-dependent. Few cells were found in intact brain; after 15 min of 4VO cells repopulated only the discrete area of CA1 cell loss, whereas with more extensive damage after 30 min occlusion cells migrated to all hippocampal fields and to cortex. A higher proportion of grafted MHP36 cells differentiated into neurons in the host CA1 field than grafts of striatal or cortical expanded cell populations. Cortical population grafts were as effective as MHP36 grafts in improving water maze learning, whereas striatal or ventral mesencephalic cells were ineffective, indicating a degree of stem cell specificity. The efficacy of MHP36 cells extends to primates. In marmosets with profound impairments in conditional discrimination tasks after lesions of the CA1 field, MHP36 cells improved performance as effectively as fetal grafts and migrated evenly through the CA1 field, in contrast to clustered fetal cells. These findings suggest that MHP36 stem cell grafts are as effective as fetal grafts in functional repair of hippocampal damage, and that their preference for areas of cell loss and adoption of appropriate morphologies is consistent with a point-to-point repair mechanism.

Immunocharacterization of H-2Kb-tsA58 transgenic mouse hippocampal neuroepithelial cells.

From dissected fragments of embryonic H-2Kb-tsA58 transgenic mouse hippocampal neuroepithelium, we have derived a population of rapidly proliferating, nestin-positive conditionally immortal hippocampal neuroepithelial cells. Treatment with dibutyryl cAMP in non-permissive culture conditions resulted in cessation of cell division and differentiation of the precursor cells into neuronal or glial phenotypes.

Foetal grafts from hippocampal regio superior alleviate ischaemic-induced behavioural deficits.

Transitory global cerebral ischaemia produced in rats by four vessel occlusion for 15 min produced substantial loss of CA1 cells in dorsal hippocampus and minimal other intra- and extra-hippocampal damage. Ischaemic rats showed a long-lasting impairment in spatial navigation in the water maze, and such impairment was sensitive to task difficulty. Groups of ischaemic animals were implanted with foetal tissue dissected from hippocampal regio superior (SUP--containing CA1 field), regio inferior (INF--containing dentate gyrus), and basal forebrain, with grafts sited in the alveus above the damaged CA1 region. Behavioral testing in the water maze (acquisition, retention and a working memory task) was conducted over a period of 4 to 12 weeks after grafting. Only rats receiving the SUP graft showed consistent improvement in water maze performance, relative to ischaemic controls, when tested in retention and working memory. Although the selective effect of CA1-containing grafts suggests repairing of the damaged host circuit, functional recovery may have been related to the greater ability of SUP grafts to survive and grow in the host ischaemic hippocampus.

Survival and distribution of transplanted human IMR-32 neuroblastoma cells.

The visualisation of transplanted cell lines is essential to determine both their viability and possible functional properties. Fluorescent latex microspheres were used to label cultured human neuroblastoma IMR-32 cells prior to transplantation. IMR-32 cells were first rendered amitotic by treatment with mitomycin C and bromodeoxyuridine and subsequently incubated with fluorescent microspheres for 3 days. Cell suspensions were prepared from these cultures and transplanted into the cortex and hippocampus of male Sprague-Dawley rats bearing ibotenate lesions of forebrain cholinergic projections. The animals were perfused at 4, 8 and 12 weeks post-transplantation and tissue was prepared for electron and light microscopy. IMR-32 cells containing fluorescent microspheres were clearly visualised in cryostat sections at all time points. Greater survival was seen in the hippocampus, with evidence of migration of cells from the site of implantation. Macrophages were seen at the electron and light microscope level, and were distinct from the discrete fluorescent labelled IMR-32 cells. Ultrastructurally, transplanted IMR-32 cells resembled cells in vitro, with microspheres clearly distinguished within the cytoplasm. Fluorescent microspheres provide a simple and direct labelling technique suitable for long-term transplant experiments using characterised cell lines.