Biomedical subjects

A Møller

Publications and source records attributed to A Møller.

At least 19 recordsLinked to original sources

PubMed2006

Exacerbated loss of cell survival, neuropeptide Y-immunoreactive (IR) cells, and serotonin-IR fiber lengths in the dorsal hippocampus of the aged flinders sensitive line "depressed" rat: Implications for the pathophysiology of depression?

Impairment of hippocampal neurogenesis has been proposed to provide a cellular basis for the development of major depression. Studies have shown that serotonin (5-HT) and neuropeptide Y (NPY) may be involved in stimulating cell proliferation in the dentate gyrus. The Flinders-sensitive line (FSL) rat represents a genetic model of depression with characterized 5-HT and NPY abnormalities in the hippocampus. Consequently, it could be hypothesized that hippocampal neurogenesis in the FSL rat would be impaired. The present study examined the relationship among 1) number of BrdU-immunoreactive (IR) cells, 2) NPY-IR cells in the dentate gyrus, and 3) length of 5-HT-IR fibers in the dorsal hippocampus, as well as volume and number of 5-HT-IR cells in the dorsal raphé nucleus, in adult and aged FSL rats and control Flinders-resistant line (FRL) rats. Surprisingly, adult FSL rats had significantly more BrdU-IR and NPY-IR cells compared with adult FRL rats. However, aging caused an exacerbated loss of these cell types in the FSL strain compared with FRL. The aged FSL rats also had shortened 5-HT-IR fibers in the dorsal hippocampus, indicative of an impaired 5-HT innervation of this area, compared with FRL. These results suggest that, for "depressed" FSL rats, compared with FRL rats, aging is associated with an excacerbated loss of newly formed cells in addition to NPY-IR cells and 5-HT-IR dendrites in the hippocampus. These observations may be of relevance to the depression-like behavior of the FSL rat and, by inference, to the pathophysiology of depression.

Aging↗

PubMed2005

Interventions for preoperative smoking cessation.

BACKGROUND: Smokers have a substantially increased risk of intra- and postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence. The preoperative period may be a well chosen time to offer smoking cessation interventions due to increased patient motivation. OBJECTIVES: The objective of this review was to assess the effect of preoperative smoking intervention on smoking cessation in the postoperative period and longer term. We also set out to determine the effect of smoking cessation on the incidence of postoperative complications. SEARCH STRATEGY: The specialized register of the Cochrane Tobacco Addiction Group was searched using the free text and keywords (surgery) OR (operation) OR (anaesthesia) or (anesthesia). MEDLINE, EMBASE and CINAHL were also searched, combining tobacco- and surgery-related terms. Most recent search February 2005. SELECTION CRITERIA: We considered randomized trials which recruited smokers prior to surgery, offered a smoking cessation intervention, and measured abstinence from smoking in the preoperative and postoperative periods. We also considered randomized trials of the effect of smoking cessation on the incidence of intra- and postoperative complications. DATA COLLECTION AND ANALYSIS: The authors independently assessed studies to determine eligibility. The results were discussed between the authors. MAIN RESULTS: Four trials met the inclusion criteria. All trials significantly reduced preoperative smoking but the effect sizes were heterogeneous so a pooled effect was not estimated. Only two trials reported the effect of the smoking intervention on wound complications, and the results were heterogeneous, with a significant reduction in wound-related complications, cardiopulmonary complications and the overall risk of any complication in one trial, and no evidence of a difference in complications in the other. The effect on longer term smoking cessation was not significant in either of the two trials with follow up beyond the perioperative period. AUTHORS' CONCLUSIONS: Preoperative smoking interventions are effective for changing smoking behaviour perioperatively. Direct evidence that reducing or stopping smoking reduces the risk of complications is based on two small trials with differing results. The impact on complications may depend on how long before surgery the smoking behaviour is changed, whether smoking is reduced or stopped completely, and the type of surgery.

Humans↗

PubMed2005

Frequency specific hearing improvement in microvascular decompression of the cochlear nerve.

BACKGROUND: Microvascular compressions of the cochlear nerve can lead to hearing loss. Due to the tonotopic organization of the cochlear nerve any focal compression of the cochlear nerve will result in a frequency specific hearing loss. Decompressing the cochlear nerve could result in a frequency specific hearing improvement, without improving overall hearing. METHOD: Thirty one patients underwent microvascular decompression operations of the vestibulocochlear nerve for vertigo or tinnitus. Preoperative audiograms were substracted from postoperative audiograms obtained 2 years after microvascular decompression. The frequencies of maximal hearing improvement postoperatively were determined. FINDINGS: Of the 31 patients studied, 19 had improvements of 5 dB or more at one or more frequencies postoperatively, and 15 patients had improvements of 10 dB or more. Three patients had improvements of 25 dB or more postoperatively. The postoperative hearing improvement was frequency-specific and related to the anatomical location of the vascular contact on the auditory nerve. The improvement of hearing becomes diluted when the difference between pre- and postoperative hearing thresholds are averaged over all audiometric frequencies. We therefore present results for each frequency that was tested. CONCLUSIONS: Microvascular decompression of the cochlear nerve can improve hearing in selected patients. The improvement seems too small to justify decompressive surgery for the sole purpose of hearing improvement, but it could be considered if associated short vertigo spells, ipsilateral tinnitus, otalgia and cryptogenic hemifacial spasm are present. Decompression should be performed early, before BAEP changes become noticeable. 3D-MRI could become a valuable tool for selecting good surgical candidates.

Adult↗

PubMed2003

Effect of antiviral therapy on markers of fibrogenesis in patients with chronic hepatitis C.

BACKGROUND: The possible markers of liver fibrosis (plasma YKL-40, PIIINP, MMP-2 and TIMP-1) were measured at the start (t0) and end of treatment (t12) with alpha-interferon and ribavirin and repeated at 6-months follow-up (t18) in 51 patients with chronic hepatitis C. METHODS: We evaluated 1) whether treatment response is reflected by a decrease in these markers during antiviral therapy; 2) whether these markers reflect the activity of the disease; and 3) whether these markers could be used as predictors of the treatment response. RESULTS: Baseline plasma YKL-40, MMP-2, PIIINP and TIMP-1 were significantly increased in patients compared to normal controls. In responders (n = 30), plasma YKL-40 (P < 0.05), MMP-2 (P < 0.05) and TIMP-1 (P < 0.001) decreased significantly at t18, and no changes were observed at t12. Plasma PIIINP was unchanged in responders. In non-responders (n = 19), plasma MMP-2 (P < 0.01) and TIMP-1 (P < 0.01) decreased significantly at t18, whereas plasma YKL-40 and PIIINP were unchanged. The markers were significantly correlated at baseline (P < 0.001). Plasma PIIINP at baseline could predict treatment response (P = 0.01). CONCLUSIONS: Response to antiviral treatment is associated with a decrease in the fibrogenetic markers, but the markers do not reflect the biochemical disease activity during treatment. Baseline plasma PIIINP was the only marker predicting treatment response.

Adipokines↗

PubMed2002

Improvement of comparability of dietary intake assessment using currently available individual food consumption surveys.

BACKGROUND: Food consumption data are used for monitoring dietary indicators of health. In this context, there is a need for comparable (individual) data at the European level. The preference is to perform a pan-European survey able to generate data collected on the same basis. Until this can be realized, the existing data have to be made as comparable as possible. OBJECTIVE: To identify solutions; to make existing food consumption data from nationally representative databases more comparable. METHODS: General guidelines for the comparison of food intake data using currently available data were discussed and agreed upon in the EFCOSUM project team. RESULTS AND CONCLUSIONS: Criteria were assessed with regard to the population involved, age of the survey, method of data collection, duration of the survey, the food classification system and the food composition tbl Based on these criteria, a maximum of 15 countries could provide food consumption data that can be made comparable at the individual level for the adult population. It is recommended to make data comparable at the food level, starting with vegetables (excluding potatoes), fruits (excluding fruit juices), fish (including shellfish) and bread. Comparability of foods is only possible at the 'raw edible' ingredient level. To achieve this, a large amount of work has to be undertaken. The approach of the EFG (Euro Food Groups) system is considered to be the best compromise between the different classification systems. Comparability at the nutrient level has to wait for the availability of a European Nutrient Database, like the one that is being developed within the EPIC context.

Adolescent↗

PubMed2002

Selection of a food classification system and a food composition database for future food consumption surveys.

OBJECTIVE: To harmonize food classification and food composition databases, allowing comparability of consumption at both food and nutrient levels in Europe. DESIGN: To establish the level of comparability at the food level, the EFCOSUM group benefited from the work already carried out within other European projects, which established a Euro Food Groups (EFG) classification system. Four food groups, ie bread, vegetables (excluding potatoes), fruits (excluding fruit juice) and fish and seafood, were judged on their applicability for making food consumption data comparable across countries at the food level. CONCLUSIONS: It was concluded that the EFG system could be used but that still much work has to be done. For food consumption data to be collected in the future, the software that will be used should enable conversion of foods 'as consumed' to foods at the 'raw edible' level. With respect to comparability of nutrient intake estimations, EFCOSUM advises waiting for the European Nutrient Composition Database (ENDB) currently being prepared by the EPIC group. Until this is available, comparison of consumption data at the nutrient level cannot be carried out between countries.

Databases, Factual↗

PubMed2002

A European food consumption survey method--conclusions and recommendations.

OBJECTIVE: To discuss the general outcome and conclusions of a European project (EFCOSUM); to develop a method for a European food consumption survey that delivers internationally comparable data on a set of policy relevant nutritional indicators. DESIGN AND METHODS: The EFCOSUM project was carried out within the framework of the European Health Monitoring Programme by 14 Member States as well as nine other European countries. Activities of the project included plenary sessions, desk research and working group activities, building on existing experience from such projects as DAFNE, EPIC, FLAIR Eurofoods-Enfant project, COST Action 99 and others. All participating states took part in one or more working group activities, which were discussed, adapted and finally approved in plenary sessions. RESULTS AND CONCLUSIONS: For a limited number of countries available food consumption data can be made comparable at the food intake level, but not at the nutrient level. To achieve comparability at the food intake level, a considerable amount of work still has to be done. A minimum list of dietary indicators considered to be the most relevant to be collected for the Health information exchange and monitoring system was identified. As the most suitable method to get internationally comparable new data on population means and distributions of actual intake the 24 h recall was selected, to be conducted at least twice. This also allows for the estimation of usual intake by a modelling technique that separates intra- and inter-individual intake. For a number of micronutrients the use of biomarkers is recommended. Aspects of food classification and food composition were discussed thoroughly, as well as statistical and data collection aspects. For the implementation of a pan-European survey the establishment of a European co-ordinating centre is recommended. The standardization of field work work procedures and other aspects of operationalization have been discussed in detail. It is concluded that there is broad European consensus on the most suitable method for a pan-European dietary survey for the purposes of the EU Health Monitoring Programme. It is further concluded that such a pan-European survey is feasible, if the funds are made available.

Data Collection↗

PubMed2002

Evaluation of Tet-on system to avoid transgene down-regulation in ex vivo gene transfer to the CNS.

Ex vivo gene transfer to the CNS has so far been hampered by instability of transgene expression. To avoid the phenomenon of transgene down-regulation, we have employed strong, constitutive promoters and compared this expression system with the inducible Tet expression system incorporated in a single plasmid vector or in lentiviral vectors. Plasmid-based transgene expression directed by the constitutive, human ubiquitin promoter, UbC, was stable in transfected HiB5 cells in vitro and comparable in strength to the CMV promoter. However, after transplantation of UbC and CMV HiB5 clones to the rat striatum, silencing of the transgene occurred in most cells soon after implantation of transfected cells. The Tet-on elements were incorporated in a single plasmid vector and inducible HiB5 clones were generated. Inducible clones displayed varying basal expression activity, which could not be ascribed to an effect of cis-elements in the vector, but rather was due, at least in part, to intrinsic activity of the minimal promoter. Basal expression activity could be blocked in a majority of cells by stable expressing the transrepressor tTS. Fully induced expression levels were comparable to CMV and UbC promoters. Similar to the constitutive promoters transgene expression was down-regulated soon after grafting of inducible HiB5 clones to the rat striatum. Lentiviral vectors can direct long-term stable in vivo transgene expression. To take advantage of this quality of the lentiviral vector, the Tet-on elements were incorporated in two lentiviral transfer vectors followed by transduction of Hib5 cells. Interestingly, all HiB5 clones established by lentiviral transduction showed very similar expression patterns and tight regulatability that apparently was independent of transgene copy number and integration site. Nevertheless, transgene expression in all lentiviral HiB5 clones was down-regulated shortly after transplantation to the rat striatum. These results confirm the general phenomenon of transgene down-regulation. Moreover, the results suggest that the considerable advantages offered by lentiviral vectors for direct gene delivery cannot necessarily be transferred directly to ex vivo gene delivery. This emphasizes the need for alternative vector strategies for ex vivo gene transfer.

Animals↗

PubMed2002

Monitoring the content and intake of trace elements from food in Denmark.

The content of cadmium, lead, nickel, mercury and selenium in 83 foods was monitored from 1993 to 1997. In comparison with similar results from 1988 to 1992, a general decrease in lead levels had occurred, whereas the contents of cadmium, nickel, mercury and selenium were stable or declined only slightly. The distribution in dietary intake of the five trace elements was estimated by combining the mean trace element concentrations with food consumption data from 1837 Danes aged 15-80 years. The lead intake for 1993-97 showed a decrease in comparison with similar estimates from the previous monitoring cycles: 1983-87 and 1988-92. The intake of cadmium and mercury decreased to a lesser extent, whereas the intake of selenium and nickel remained unchanged in the same period. The dietary intake of trace elements was compared with the provisional tolerable weekly intake (PTWI). The 95th percentile of the distribution in cadmium intake amounts to 34% of PTWI, which is relatively high, and therefore calls for a more detailed future risk assessment. The intakes of lead and mercury were 11% of PTWI and, like the intake of nickel, did not cause any health concern in the adult population. The Danes ingest close to 100% of the Nordic Nutrition Recommendation for selenium at 50 microg day(-1), and no individuals had an intake less than the lower limit of 20 microg day(-1).

Adolescent↗

PubMed2002

Dynamic online sewer modelling in Helsingborg.

Within the last decade, the sewer system in Helsingborg, Sweden has been rehabilitated in many ways along with the reconstruction of the WWTP Oresundsverket in order to obtain a high degree of nitrogen and phosphorus removal. In that context a holistic view has been applied in order to optimise the corrective measures as seen from the effects in the receiving waters. A sewer catchment model has been used to evaluate several operation strategies and the effect of introducing RTC. Recently, a MOUSE ONLINE system was installed. In this phase the objective is to establish a stable communication with the SCADA system and to generate short-term flow forecasts.

Computer Simulation↗

PubMed2002

Interferon alfa-2b alone or combined with recombinant granulocyte-macrophage colony-stimulating factor as treatment of chronic hepatitis C.

BACKGROUND: To compare the effect of combination therapy with interferon-alpha (INF-alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF) to monotherapy with INF-alpha in patients with chronic hepatitis C infection. METHODS: Forty-five consecutive patients with chronic hepatitis C, all presenting with elevated serum alanine aminotransferases and viremia, were randomized to receive either 1) INF-alpha + GM-CSF for 3 months followed by INF-alpha alone for 9 months (n = 23) or 2) INF-alpha for 12 months (n = 22). Both drugs were administered 3 times weekly in doses of 3 mU (INF-alpha) and 50-100 microg depending on body weight (GM-CSF). RESULTS: At baseline, there was no difference between the treatment groups in terms of age, sex, ALT level, viral load, genotype or histological activity and fibrosis in a pretreatment liver biopsy. After 12 months' treatment, more patients treated with GM-CSF+ INF-alpha compared to patients receiving monotherapy had normalized ALT, 65% and 32%, respectively (P = 0.03), but there was no difference in percentages of patients with viral clearance between the 2 groups, 48% and 32%, respectively (P = 0.27). At 6 months' follow-up, the biochemical response had declined to 35% in the combination therapy group and to 23% in the monotherapy group (P = 0.37); viral clearance had declined to 22% and 27%, respectively (P = 0.67), and the overall sustained response rate was 22% and 23%, respectively (P = 1.00). CONCLUSIONS: Even though patients receiving INF-alpha + GM-CSF had a significant better biochemical response during treatment compared to patients receiving monotherapy, the sustained biochemical and virological response was not increased. Thus, GM-CSF hardly plays any role in the future treatment of chronic hepatitis C.

Adult↗

PubMed2001

Evaluation of CA1 damage using single-voxel 1H-MRS and un-biased stereology: Can non-invasive measures of N-acetyl-asparate following global ischemia be used as a reliable measure of neuronal damage?

Global brain ischemia provoked by transient occlusion of the carotid arteries (2VO) in gerbils results in a severe loss of neurons in the hippocampal CA1 region. We measured the concentration of the neuron specific N-acetyl-aspartate, [NAA], in the gerbil dorsal hippocampus by proton MR spectroscopy (1H-MRS) in situ, and HPLC, 4 days after global ischemia. The [NAA] was correlated with graded hippocampus damage scoring and stereologically determined neuronal density. A basal hippocampal [NAA] of 8.37+/-0.10 and 9.81+/-0.44 mmol/l were found from HPLC and 1H-MRS, respectively. HPLC measurements of [NAA] obtained from hippocampus 4 days after 2VO showed a 20% reduction in the [NAA] following 4 min of ischemia (P<0.001). 1H-MRS measurements on gerbils subjected to 4 or 8 min of ischemia showed a similar 24% decline in the [NAA] (P<0.05). Thus, there was correlation between the HPLC and 1H-MRS determined NAA decline. There was also a significant correlation between 1H-MRS [NAA] and the corresponding reduction in CA1 neuronal density (P<0.004). In summary our findings show that single voxel 1H-MRS can be used as a supplement to histological evaluation of neuronal injury in studies after global brain ischemia. Accordingly, volume selective spectroscopy has a potential for assessment of neuroprotective therapeutic compounds/strategies with respect to neuronal rescue for delayed ischemic brain damage.

Animals↗

PubMed2001

Interventions for preoperative smoking cessation.

BACKGROUND: Smokers have a substantially increased risk of intra and postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence. The preoperative period may be a well chosen time to offer smoking cessation interventions due to increased patient motivation. OBJECTIVES: The objective of this review was to assess the effect of preoperative smoking intervention on smoking cessation in the postoperative period and longer term. We also set out to determine the effect of smoking cessation on the incidence of postoperative complications. SEARCH STRATEGY: The specialised register of the Tobacco Addiction Group was searched using the free text and keywords (surgery) OR (operation) OR (anaesthesia) or (anesthesia). The databases "EMBASE" and "CINAHL" were also searched, combining tobacco and surgery related terms. SELECTION CRITERIA: We considered randomised trials which recruited smokers prior to surgery, offered a smoking cessation intervention, and measured abstinence from smoking in the pre-operative and post-operative periods. We also considered randomised trials of the effect of smoking cessation on the incidence of intra and post-operative complications. DATA COLLECTION AND ANALYSIS: The reviewers independently assessed studies to determine eligibility. The results were discussed between the reviewers. MAIN RESULTS: No trial meeting the inclusion criteria was found. REVIEWER'S CONCLUSIONS: We found no evidence to determine the effectiveness of pre-operative interventions in helping people to stop smoking, or of the effectiveness of smoking cessation in reducing peri-operative complications. However, observational evidence suggests benefits in stopping smoking before surgery. Although there is no direct evidence about which interventions work best in patients preparing for surgery, behavioural and pharmacological interventions shown to be effective in other settings should be considered.

Humans↗

PubMed2001

Stereological cell counts of GABAergic neurons in rat dentate hilus following transient cerebral ischemia.

We have previously demonstrated a 60-80% ischemic loss of somatostatinergic neurons in the dorsal dentate hilus of the rat. However, several studies have failed to demonstrate ischemic loss of GABAergic neurons in hilus, although one study reports that 96% of the somatostatinergic neurons in the dorsal hilus colocalize GABA. In order to understand this paradox, we have now estimated, using unbiased stereology, the total number of neurons immunohistochemically stained against glutamic acid decarboxylase-65 (GAD65) and GAD67 in the dorsal dentate hilus. Rats were divided into groups subjected to either sham operation (n=8) or 8 min of transient global ischemia during systemic hypotension (n=8) and allowed to survive for 7-9 days. Results from cell counts (mean +/- SD) in sham rats demonstrated that the dorsal hilus contains 9,189+/-3,957 GAD65 neurons and 6,991+/-2,784 GAD67 neurons. After ischemia, corresponding cell counts demonstrated 10,216+/-4,866 GAD65 neurons and 10,119+/-5,906 GAD67 neurons, and these results were not significantly different (P>0.05) from results in sham rats. Power analysis of the t-test informs that losses less than 80% are not significant and reflects the excessive variance in our material. For comparison, we estimated a total of 21% ischemic neuron death in the dorsal hilus on cresyl violet-stained sections from other corresponding sham (n=7) and ischemic rats (n=7). This explains why ischemic loss of hilar GABAergic neurons can only be detected by counts of the vulnerable subpopulation colocalizing somatostatin. Our investigation has demonstrated a surprisingly high variation between rats in a number of GAD-immunopositive neurons located in the dorsal dentate hilus, which is related to variations between the individual rats and neurons in their endogenous GAD expression.

Animals↗

PubMed2001

Normalization of markers for dopamine innervation in striatum of MPTP-lesioned miniature pigs with intrastriatal grafts.

As part of the DaNeX study, the uptake and binding of several positron emitting tracers was recorded in brain of healthy Göttingen minipigs, in minipigs with a syndrome of parkinsonism due to MPTP intoxication, and in parkinsonian minipigs which had received intrastriatal grafts of mesencephalic neurons from fetal pigs. The specific binding of [11C]NS 2214 to catecholamine uptake sites was reduced by two thirds in striatum of the intoxicated animals, while the rate constant for the decarboxylation of [18F]fluorodopa was reduced by 50% in the intoxicated animals. Several months after grafting, both pre-synaptic markers of dopamine fibres were normal in striatum. Dopamine depletion or grafting were without effect on the cerebral perfusion rate, measured with [15O]-water, did not alter the rate of oxygen metabolism (CMRO2) in brain, and did not alter the binding potential of tracers for dopamine D1 or D2 receptors in pig striatum. However, the grafting was associated with a local increase in the binding of [11C]PK 11195, a tracer for reactive gliosis, suggesting that an immunological reaction occurs at the site of graft, which might potentially have reduced the graft patency. However, this apparent immunological response did not preclude the re-establishment of normal [18F]fluorodopa and [11C]NS 2214 uptake in the allografted striatum.

Animals↗

PubMed2001

Changing demographics in an HIV-infected population: results from an observational cohort study in Western Denmark.

We present demographic data from an observational database of HIV and AIDS in the Western part of Denmark, a region with a population of 2,935,156 individuals (55.1% of the population of Denmark). Five centers in the region treat HIV-positive adults; all patients attached to these centers since 1995 are included in this study. In total, 749 adult HIV-infected individuals were enrolled as of 31 December, 1999. Estimates of prevalence and incidence of HIV infection in the area were 25.9/100,000 and 2.6/100,000, respectively, which are lower than average for the country. The number of newly diagnosed HIV-infected patients remained constant during the period 1995-99, with an average of 62 diagnoses per year. The number of HIV-related deaths declined from 43 in 1995 to 15 in 1999. Of the enrolled patients, 70.9% were of Danish origin, 75% were Caucasians, 69.7% were male and 47.2% had heterosexual contact as their primary risk behavior. There seems to have been a shift in the HIV epidemic in recent years, with a higher proportion of newly diagnosed HIV patients having contracted the infection through heterosexual contact, a higher proportion being immigrants from less developed countries and newly diagnosed individuals getting older.

Adult↗

PubMed2000

[Familial Mediterranean fever in a 26-year old Lebanese man].

FMF is a hereditary disorder characterised by periodic fever and acute abdominal, chest, or joint pain. In the long term, amyloidosis may develop and eventually result in kidney failure. A 26-year-old man from Lebanon was diagnosed with FMF by genetic testing and treated with colchicine for two months. Colchicine reduced the frequency, duration, and intensity of his attacks, and thus minimised the risk of amyloidosis developing.

Adult↗

PubMed2000

A simple procedure for quantification of neurite outgrowth based on stereological principles.

The molecular mechanisms controlling formation and remodelling of neuronal extensions are of considerable interest for the understanding of neuronal development and plasticity. Determination of neurite outgrowth in cell culture is a widely used approach to investigate these phenomena. This is generally done by a time consuming tracing of individual neurites and their branches. We have used stereological principles to determine the length of neurites. The total neuritic length per cell was estimated by counting the number of intersections between neurites and test lines of an unbiased counting frame superimposed on images of cell cultures obtained by conventional computer-assisted microscopy. The absolute length, L, of neurites per cell was subsequently estimated from the number of neurite intersections, I, per cell by means of the equation L=(pid/2)I describing the relationship between the number of neurite intersections and the vertical distance, d, between the test lines used. When measuring neurite outgrowth from PC12 cells and primary hippocampal neurons, data obtained by counting neuritic intersections correlated statistically significantly with data obtained using a conventional tracing technique. However, information was acquired more efficiently using the stereological approach. Thus, using the described set-up, the stereological procedure was approximately five times less time consuming than the conventional method based on neurite tracing. The study shows that stereological estimation of neuritic length provides a precise and efficient method for the study of neurite outgrowth in cultures of primary neurons and cell lines.

Animals↗