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Objectives: This study investigated whether the association between modifiable dementia risk and rate of cognitive decline differs across socioeconomic status (SES) strata., Design, Setting and Participants: Data were used from Maastricht Aging Study, a prospective cohort study with a 12-year follow-up. The baseline sample consisted of 1023 adults over 40 years old., Measurements: The "LIfestyle for BRAin health" (LIBRA) index was used to assess modifiable dementia risk. Cognitive performance was assessed at baseline, 6 and 12 years, and measured in the domains of information processing speed, executive functioning and verbal memory function. An SES score was calculated from equivalent income and educational level (tertiles). Linear mixed models were used to study the association between LIBRA, SES and their interaction on the rate of cognitive decline., Results: Participants in the lowest SES tertile displayed more decline in information processing speed (vs. middle SES: X 2 = 7.08, P = 0.029; vs. high SES: X 2 = 9.49, P = 0.009) and verbal memory (vs. middle SES: X 2 = 9.28, P < 0.001; vs. high SES: X 2 = 16.68, P < 0.001) over 6 years compared to their middle- and high-SES counterparts. Higher (unhealthier) LIBRA scores were associated with more decline in information processing speed (X 2 = 12.66, P = 0.002) over 12 years and verbal memory (X 2 = 4.63, P = 0.032) over 6 years. No consistent effect modification by SES on the association between LIBRA and cognition was found., Conclusions: Results suggest that lifestyle is an important determinant of cognitive decline across SES groups. Yet, people with low SES had a more unfavorable modifiable risk score suggesting more potential for lifestyle-based interventions.

Objective: It is estimated that about 40% of all dementia cases are potentially attributable to modifiable risk factors, but awareness of this is relatively lacking., Methods: An 18-months nation-wide public awareness campaign on dementia risk reduction was rolled out in Denmark that combined a mass-media approach with an online risk assessment tool and knowledge bank targeting all inhabitants aged between 40 and 75 years. Campaign effects (increase in awareness and knowledge of modifiable dementia risk and protective factors) were assessed via online surveys in two independent random samples before (n = 1003) and after the campaign (n = 1076)., Results: After adjusting for differences in educational level between the two samples, there was no significant difference in awareness of dementia risk reduction between the pre-campaign (66.5% aware) and post-campaign (63.4% aware) sample (probit z = -0.08, p = 0.151). The number of correctly identified risk/protective factors was significantly higher in the post-campaign sample. After adjusting for potential confounding factors, self-reported exposure to the campaign was associated with more awareness, better recognition of risk/protective factors, more motivation for and actual implementation of lifestyle changes., Conclusions: This mass-media campaign did not increase overall awareness that dementia risk is partly modifiable. However, exposure to the campaign was associated with more awareness and willingness to take action to improve brain health. Future campaigns should tailor messages to specific subgroups to broaden the reach (e.g., males), co-create materials with the target group, and give special attention to the contribution of metabolic/cardiovascular risk factors to dementia risk., Competing Interests: Declaration of competing interest None., (Copyright © 2023. Published by Elsevier Inc.)

Background: Unhealthy behavior increases the risk of dementia. Various socio-cognitive determinants influence whether individuals persist in or alter these unhealthy behaviors., Objective: This study identifies relevant determinants of behavior associated to dementia risk., Methods: 4,104 Dutch individuals (40-79 years) completed a screening questionnaire exploring lifestyle behaviors associated with dementia risk. Subsequently, 3,065 respondents who engaged in one or more unhealthy behaviors completed a follow-up questionnaire investigating socio-cognitive determinants of these behaviors. Cross-tables were used to assess the accuracy of participants' perceptions regarding their behavior compared to recommendations. Confidence Interval-Based Estimation of Relevance (CIBER) was used to identify the most relevant determinants of behavior based on visual inspection and interpretation., Results: Among the respondents, 91.3% reported at least one, while 65% reported two or more unhealthy lifestyle behaviors associated to dementia risk. Many of them were not aware they did not adhere to lifestyle recommendations. The most relevant determinants identified include attitudes (i.e., lacking a passion for cooking and finding pleasure in drinking alcohol or smoking), misperceptions on social comparisons (i.e., overestimating healthy diet intake and underestimating alcohol intake), and low perceived behavioral control (i.e., regarding changing physical inactivity, altering diet patterns, and smoking cessation)., Conclusions: Individual-level interventions that encourage lifestyle change should focus on enhancing accurate perceptions of behaviors compared to recommendations, while strengthening perceived control towards behavior change. Given the high prevalence of dementia risk factors, combining interventions at both individual and environmental levels are likely to be the most effective strategy to reduce dementia on a population scale.

Background: Evidence on modifiable risk factors for dementia is accumulating rapidly, including e.g. smoking, hypertension, and diabetes. Comparing knowledge of risk factors for dementia and factors associated with knowledge and motivation to learn about dementia risk reduction in different countries may support the design of tailored public health campaigns. We investigated (1) differences in knowledge of risk and protective factors for dementia between the Netherlands and Germany, and interest in (2) information on brain health and (3) eHealth for brain health., Materials and Methods: Population-based telephone (Germany) or web-based surveys (Netherlands) were conducted among adults aged 60-75 (n total =614; Germany: n = 270; Netherlands: n = 344), assessing sociodemographic factors, knowledge of risk and protective factors for dementia, interest in information on brain health and respective eHealth-tools. Correlates of knowledge, interest in information on brain health and eHealth for brain health were analyzed using multivariable regression, by country and in pooled analyses., Results: In the total sample (M age : 67.3 (SD: 4.3) years; % female : 48.6), knowledge of risk and protective factors (sum score assessing number of correctly identified factors) was higher among German participants (M (SD) = 7.6 (2.5) vs. 6.0 (4.3), p < .001). This was confirmed using linear regression analyses, controlling for sociodemographic covariates (b = 1.51; 95% CI: 1.00; 2.01). High education was linked to better knowledge of risk and protective factors (b = 1.61; 95% CI: 0.89; 2.34). Controlling for covariates, interest in information on brain health (OR: 0.05, 95% CI: 0.02; 0.09) and eHealth for brain health (OR: 0.40, 95% CI: 0.25; 0.65) was lower in German participants. Widowed participants were less interested in information on brain health, while widowed and single participants expressed less interest in eHealth for brain health in pooled analyses. Further associations between sociodemographic factors, interest in information on brain health and eHealth for brain health by country were detected., Discussion: Engaging older adults in the design of eHealth interventions and cooperation with trusted sources, e.g., general practitioners, might enhance appreciation of eHealth for brain health. Education on risk and protective factors for dementia is warranted in both countries. However, differences in recruitment and assessment need to be acknowledged., (© 2023. The Author(s).)

Background: Health- and lifestyle factors account for a substantial part of all dementia cases, which opens the opportunity for primary prevention. However, the required behavioral change is complex and involves targeting multiple risk factors. mHealth interventions can potentially contribute to improving motivation in a low-cost and scalable way., Objective: To explore usage patterns, appreciation, and beliefs and attitudes regarding dementia risk reduction during the use of the MyBraincoach mobile app., Methods: Participants were community-dwelling middle-aged adults from the Netherlands and used either the standard (education) or extended (education+motivational triggers) app version for three months. Two panel studies were combined in this paper. Chi-square tests, t-tests and linear mixed models were used, adjusted for age, sex, and education., Results: Of all participants (n = 299, 50.2% male), 167 (55.9%) had installed the app. The most reported reason for non-use was technical problems (47%). Those who used the app were at baseline already more positive about dementia risk reduction than those who did not use the app. Of all users who completed the evaluation (n = 102), 78.4% (n = 80) stated that the app provided a positive approach towards brain health and 80.4% (n = 82) felt better informed. Younger (<60y) and lower educated participants evaluated the app most positively., Conclusion: Usage of the app was low, but users showed more positive beliefs and attitudes regarding dementia risk reduction. Most users evaluated the app positively and stated to have gained knowledge on the topic. Improving the use of the app must keep high priority in future studies.

Background: There is accumulating evidence that addressing modifiable risk and protective factors has an impact on dementia rates. Insight into the public's perspectives on dementia risk reduction is needed to inform future individual-level interventions and public health approaches., Objective: This study explores the publics' openness towards dementia risk reduction and willingness towards changing lifestyle behavior to reduce the future risk for dementia., Methods: Using a screening questionnaire, participants were purposively selected based on lifestyle behaviors that are associated with dementia risk. One-on-one interviews were used to explore their openness towards dementia risk reduction and willingness towards behavior change. Independently, two researchers performed an inductive content analysis., Results: Interviews were conducted with 23 participants aged from 40 to 79 years. Main themes that were identified from the data were: 1) abstractness of dementia risk reduction, 2) ambivalence towards changing behavior, 3) negative self-image and low behavioral control, and 4) all-or-nothing thinking about lifestyle change., Conclusions: The concept of dementia risk reduction seems difficult to translate to the personal context, particularly if individuals perceive that dementia would occur decades in the future. This is problematic because a large proportion of the public needs a healthier lifestyle to reduce the incidence of dementia. Translating healthy intentions into behavior is complex and involves overcoming a variety of barriers that complicate dementia risk reduction initiatives. Support is needed for individuals who experience additional obstacles that obstruct commencing to a healthier lifestyle (e.g., negative self-image, engaging in multiple unhealthy behaviors, unrealistic perceptions about lifestyle change).

Introduction: Behaviour change interventions represent key means for supporting healthy ageing and reducing dementia risk yet brief, scalable behaviour change interventions targeting dementia risk reduction in older adults is currently lacking. Here we describe the aims and design of the three-month Brain Bootcamp initiative that seeks to target multiple dementia risk and protective factors (healthy eating, physical, social and cognitive inactivity), through the use of multiple behaviour change techniques, including goal-setting for behaviour, information about health consequences and physical prompts to change behaviours that reduce dementia risk among older adults. Our secondary aim is to understand participants' views of dementia prevention and explore the acceptability and integration of this campaign into daily life., Methods: Brain Bootcamp is a pre-post feasibility trial conducted in Sydney, Australia beginning in January 2021 until late August. Participants aged ≥65 years living independently in the community (n = 252), recruited through social media and flyers, will provide information about their demographics, medical history, alcohol consumption, smoking habits, mental health, physical activity, cognitive activity, and diet to generate a dementia risk profile at baseline and assess change therein at three-month follow-up. During the intervention, participants will receive a resource pack containing their individual risk profile, educational booklet on dementia risk factors and four physical items designed to prompt physical, social and mental activity, and better nutrition. Outcome measures include change in dementia risk scores, dementia awareness and motivation. A qualitative process evaluation will interview a sample of participants on the acceptability and feasibility of the intervention., Discussion: This will be the first short-term multi-domain intervention targeting dementia risk reduction in older adults. Findings will generate a new evidence base on how to best support efforts targeting lifestyle changes and to identify ways to optimise acceptability and effectiveness towards brain health for older adults., Trial Registration Number: ACTRN 381046 (registered 17/02/2021); Pre-results., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Siette et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

This study evaluates a public health campaign initiated by the Alzheimer Center Limburg of Maastricht University. The aim was to increase awareness of the influence of a healthy lifestyle on lowering the risk of dementia in community-dwelling inhabitants of the Province of Limburg (aged 40 - 75 years). The campaign used mass media and public events, supported by a campaign website and mobile application (MijnBreincoach app).  An additional district-oriented approach was chosen in the municipalities of Roermond, Landgraaf and Brunssum, in which local stakeholders were involved in the design and execution of campaign-related events. Population-level difference in awareness before and after the campaign was assessed in two independent samples. No pre-post difference was observed in the level of awareness of dementia risk reduction. An additional analyses in the post-campaign sample revealed that the group that reported to have heard of the campaign, was more often aware of dementia risk reduction and reported higher motivation for behavioural change than the group that had not heard of the campaign. The district-oriented approach resulted in better recognition of campaign-material and the mobile application. With regard to the individual lifestyle factors, healthy diet and physical activity were identified more often post-campaign. Cognitive activity was identified most often at both pre- and post-assessment, but there was no increase in awareness after the campaign.

Strategies to reduce dementia risk are needed to minimize the burden of this growing public health concern. Most individuals are not aware that dementia risk reduction is possible, let alone how this could be achieved. Health education, such as public awareness campaigns on the topic of dementia risk reduction, can meet this need. A public health campaign (including social media and offering an online individual risk assessment tool) was carried out over a 7-month period in Flanders, Belgium. Impact was assessed in two independent online surveys, before (n = 1003) and after the campaign (n = 1008), in representative samples of adults aged 40-75 years. Questions regarding personal needs, wishes and barriers were also included. After the campaign, more individuals (10.3%) were aware that dementia risk reduction is possible than before the campaign, and more individuals correctly identified 10 out of 12 surveyed modifiable dementia risk and protective factors. However, no differences were observed in low-educated individuals. Further, specific differences in potential needs, wishes and barriers for future campaigns or interventions were observed between demographic strata. The majority of the respondents (89%) indicated that they would welcome more information on improving their brain-health. More than half (54%) also believed that they lacked the necessary knowledge to make brain-healthy behavior changes. In conclusion, effective public awareness campaigns on the topic of dementia risk reduction are feasible and timely, given the state of the evidence. Special efforts need to be made to develop effective campaigns, tailored towards low-educated individuals., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Evaluate the effect of a health promotion campaign aimed at increasing awareness about dementia risk reduction in middle-aged community-dwelling individuals in the Netherlands., Design: A 10-month public health campaign using mass media and community participation, supported by eHealth. Population-level difference in awareness before and after the campaign, including variation between demographic groups, was assessed in two independent cross-sectional samples from the same target population., Setting: The public health campaign was launched in the Province of Limburg, the Netherlands, targeting all inhabitants aged 40-75 years old. Three specific districts within the Province were chosen for an additional community participation approach, in which local stakeholders were invited to support the campaign., Results: No pre- (n=590) post- (n=602) difference was observed in people agreeing to the statement that dementia risk reduction is possible (X 2 (1)=1.27, p=0.260). For the individual lifestyle factors, physical activity (7.6% increase (X 2 (1)=7.48, p=0.006)) and healthy diet (10.5% increase (X 2 (1)=12.37, p≤0.001)) were identified more often as being protective against dementia after the campaign. Of all risk/protective factors assessed, cognitive activity was identified most often at both preassessment (79.4%) and postassessment (80.4%), but there was no increase in awareness (X 2 (1)=0.17, p=0.677). Self-reported exposure to the campaign was associated with greater awareness and motivation for behavioural change (X 2 (1)=6.52, p=0.011). Compared with mass media only, the addition of community participation resulted in better recognition of campaign material and the eHealth platform., Conclusions: This study was not able to reach a population-level increase of awareness of dementia risk reduction. Two out of the three lifestyle factors that formed the foundation of the campaign were identified more often after the campaign. Those reported having been exposed to the campaign were more aware and more inclined towards behavioural change., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The total number of people with dementia is increasing worldwide, due to our aging society. Without a disease-modifying drug available, risk reduction strategies are to date the only promising way to reduce dementia incidence in the future. Substantial evidence exists that lifestyle factors contribute to the risk of dementia, such as physical exercise, mental activity and (non-)smoking. Still, most people seem unaware of a relationship between lifestyle and brain health. This paper investigates dementia literacy and knowledge of modifiable risk and protective factors of dementia in a Dutch population-based sample., Methods: An online-survey was carried out among 590 community-dwelling people between 40 and 75 years old in the Province of Limburg, the Netherlands. The total group comprises both of a provincial sample (n = 381) and a sample of three specific districts within the province (n = 209). Dementia awareness and knowledge about 12 risk and protective factors was assessed with items derived from the British Social Attitudes (BSA) survey, supplemented with custom items developed by the research team., Results: The majority of participants (56%) were unaware of a relationship between lifestyle and dementia risk. Most individuals identified low cognitive activity, physical inactivity and unhealthy diet as dementia risk factors. Particular gaps in knowledge existed with regard to major cardiovascular risk factors such as hypertension, hypercholesterolemia and coronary heart disease. Although the level of awareness varied by age and level of education, most people (70%) were eager to learn more about the topic of brain health, and indicated to be interested in using eHealth (54%) to measure or improve brain health., Conclusions: Most people still are unaware of the relation between lifestyle and brain health, indicating the need for public health campaigns. Increasing awareness in the general population about the presence of modifiable dementia risk and protective factors is a crucial first step prior to implementation of preventative measures. Targeting specific subgroups, such as individuals with low socioeconomic status and low health literacy, is essential for the reach and effect of a prevention campaign. Outcome of this study was the rationale for an awareness campaign in The Netherlands, called "MijnBreincoach" ("MyBraincoach").

Optic nerve sheath diameter (ONSD) measured by transocular ultrasound is a marker of real-time intracranial pressure (ICP). The objective of this study was to evaluate the association between optic nerve sheath (ONS) dilation after a Valsalva maneuver and a prior history of mild to moderate traumatic brain injury (mTBI) in a heterogeneous sample of participants. Participants were excluded if they had had a recent brain injury, were symptomatic from a prior brain injury, had a history consistent with severe TBI and/or had undergone intracranial surgery. Ninety-five participants with and without a history of mTBI were included in the study. Transocular ultrasound of the ONS was performed before and after a Valsalva maneuver. Differences in the ONSD before and after a Valsalva maneuver were analyzed and correlated to the participants' history of mTBI. Baseline ONSD measurements between groups were not statistically significant. Following Valsalva, participants with a history of mTBI had a statistically significant increase in the ONSD compared with participants with no history of mTBI. This significant difference persisted after controlling for age, race, and sex. This study demonstrated an association between a prior history of mTBI and dilation of the ONS after Valsalva maneuver in a sample of asymptomatic participants, which was not seen in participants without a history of mTBI.

A 9-year-old boy with spina bifida, Chiari II malformation, and hydrocephalus presented with signs of increased intracranial pressure consistent with a shunt malfunction. Radiological investigations revealed an intracranial calcified lesion along the ventricular catheter. A shunt tap revealed a translucent milky white fluid. The patient underwent a ventriculostomy and, eventually, a shunt revision. Pathology findings were consistent with the formation of dystrophic calcification and a pseudocyst around the shunt catheter. Postoperatively, the patient returned to his neurological baseline. This is, to the best of the authors' knowledge, the first report of an intracranial calcified pseudocyst in a patient with normal renal function.

We demonstrate a novel method of endoscopic frontal-orbital advancement for the treatment of unicoronal craniosynostosis. The evolution of this cranioplasty modality burrows from an established precedent of safety and technical experience in strip craniectomies and endoscopic brow surgery. The procedure facilitates osteotomies similar to open frontal-orbital advancement and uses reabsorbable materials to achieve immediate intraoperative correction of unicoronal craniosynostosis through smaller incisions. The patients in the study underwent endoscopic frontal-orbital advancement and cranial vault remodeling. This was made possible with the use of a novel ultrasonic bone saw that permits osteotomies to be made with minimal disruption to the dura matter. After full frontal-orbital advancement, immediate reabsorbable fixation was used to stabilize the advancement as in the open technique. There were no major complications. All patients demonstrated improvement in plagiocephaly due to unilateral coronal synostosis. Patients and their families reported a 100% patient satisfaction and an improvement in cranial asymmetry from 10 to 2 mm (P < 0.5). This is a new endoscopic cranial vault remolding technique that achieves state-of-the-art correction of unicoronal craniosynostosis with less morbidity and mortality.

Objective: The pathophysiological effects of syrinx distension are incompletely understood. Although it is generally assumed that the accumulation of fluid within syrinx cavities can contribute to neurological dysfunction, there are no reports describing intramedullary pressure in syringomyelia. The purpose of the current study was to measure syrinx pressures in patients with progressive clinical deterioration and to correlate these data with neurological deficits and intraoperative physiological findings., Methods: Intramedullary fluid pressure was measured manometrically in 32 patients undergoing syrinx shunting procedures. The data were correlated with syrinx morphology, intraoperative somatosensory evoked potentials, laser Doppler measurements of local spinal cord blood flow (six patients), and neurological findings before and after syrinx decompression., Results: Syrinx pressures recorded under atmospheric conditions ranged from 0.5 to 22.0 cm H2O (mean = 7.7 cm). There was a significant elevation of the cardiac pulse (mean = 0.7 cm H2O) and the respiratory pulse (mean = 1.1 cm H2O) that was consistent with raised cerebrospinal fluid pressure. Syrinx pressures decreased to subatmospheric levels after surgical drainage. In 18 of 24 patients with predrainage somatosensory evoked potential abnormalities, syrinx decompression produced a consistent reduction of N20 latencies (mean change = 0.49 ms +/- 0.094 SE right, P = 0.002; 0.61 ms +/- 0.089 SE left, P = 0.001) and a similar but less consistent increase in N20 amplitudes (mean change = 0.17 mV +/- 0.103 SE right, P = 0.115; 0.31 mV +/- 0.097 SE left, P = 0.027). Measurements of local spinal cord blood flow revealed very low baseline values (mean = 12.2 arbitrary units +/- 13.9 standard deviation), which increased to intermediate levels (mean = 144.7 arbitrary units +/- 42.6 standard deviation) after syrinx decompression. Patients with syrinx pressures greater than 7.7 cm H2O tended to have more rapidly progressive symptoms, exhibited greater improvements after shunting, and had a higher incidence of postoperative dysesthetic pain., Conclusion: The current study is the first to measure intramedullary pressure in a human disease. Evidence is presented that distended syringes are associated with varying levels of raised intramedullary pressure that can accentuate or induce neurological dysfunction by the compression of long tracts, neurons, and the microcirculation. Symptoms referrable to raised intramedullary pressure are potentially reversible by syrinx decompression.

Analysis of the mechanisms of loosening of cemented stems by radiological long-term follow-up in 129 cases. The most important finding was the failure of the cement-metal interface (29.5%), which was correlated significantly with osteolysis (31%). This suggests that the polyethylene debris reaches the bone through defects in the cement mantle (76.7%). In fact, the appearance of cement defects matches the number of identified osteolyses. This study shows that no permanent fixation can be achieved by the surface roughness of 2.0 microns Ra tried herein.

Laser-Doppler flowmetry (LDF) provides a reliable measurement of local cerebral blood flow (lCBF) as demonstrated by multiple validation studies. This article evaluates the clinical applications of LDF in neurosurgery. With the availability of modified probes, it is possible to carry out LDF monitoring of neurosurgical patients in the intensive care unit. Currently, there are multiple systemic and intracranial parameters that are interactive and separately monitored. A multi-channeled digital data acquisition system allows these data to be compiled in a single computer environment for the interpretation of lCBF changes. Guidelines are suggested for the clinical use of LDF monitoring, and the technical features of monitoring including the interpretation of data are summarized.

Hindbrain lesions that distort or compress the cervicomedullary junction are commonly associated with syringomyelia. As a basis for discussing pathogenetic mechanisms, the upper end of the central canal of the spinal cord was examined histologically in six aborted fetuses and 14 adults dying of natural causes; the results were correlated with magnetic resonance images in 40 normal subjects. The central canal of the medulla, which extends from the cervicomedullary junction to the fourth ventricle, was found to migrate dorsally, elongate in dorsoventral diameter, and dilate beneath the tip of the obex to form a large, everted aperture. This opening communicates directly with the subarachnoid space through the foramen of Magendie and is indirectly continuous with the main body of the fourth ventricle. In adults, the aperture of the central canal is located approximately 1.0 cm below the tela choroidea inferior and 3.5 cm below the midpoint of the fourth ventricle. Analysis of magnetic resonance imaging scans in 45 patients with syringomyelia and simple hindbrain lesions revealed two patterns of cavity formation: 1) lesions that obstructed the upper end of the central canal or its continuity with the subarachnoid space produced a noncommunicating type of syringomyelia; and 2) lesions that obstructed the basilar cisterns or the foraminal outlets of the fourth ventricle produced a communicating type of syringomyelia (hydromyelia) in association with hydrocephalus. Evidence is presented that syrinxes occurring with hindbrain lesions are not caused by a caudal flow of cerebrospinal fluid from the fourth ventricle into the central canal of the spinal cord.

The pathology of hematomyelia was examined in 35 rats following the stereotactic injection of 2 microliters blood into the dorsal columns of the thoracic spinal cord. This experimental model produced a small ball-hemorrhage without associated neurological deficits or significant tissue injury. Histological sections of the whole spinal cord were studied at intervals ranging from 2 hours to 4 months after injection. In acute experiments (2 to 6 hours postinjection), blood was sometimes seen within the lumen of the central canal extending rostrally to the level of the fourth ventricle. Between 24 hours and 3 days, the parenchymal hematoma became consolidated and there was an intense proliferation of microglial cells at the perimeter of the lesion. The cells invaded the hematoma, infiltrated its core, and removed erythrocytes by phagocytosis. Rostral to the lesion, the lumen of the central canal was found to contain varying amounts of fibrin, proteinaceous material, and cellular debris for up to 15 days. These findings were much less prominent in the segments of the canal caudal to the lesion. Healing of the parenchymal hematoma was usually complete within 4 to 6 weeks except for residual hemosiderin-laden microglial cells and focal gliosis at the lesion site. It is concluded that the clearance of atraumatic hematomyelia probably involves two primary mechanisms: 1) phagocytosis of the focal hemorrhage by microglial cells; and 2) drainage of blood products in a rostral direction through the central canal of the spinal cord.

The preparation of the aminomethyl-bilinogen which results from formal "head to tail" condensation of porphobilinogen is described. The chemical cyclocondensation of this compound at pH 7.4 yields uroporphyrinogen I. Enzymatic studies with enzyme preparations from Propionibacterium shermanii, which synthesize uroporphyrinogens from porphobilinogen, show that the rate of cyclisation is increased by these enzymes and indicate that the bilinogen also might be used for uroporphyrinogen III formation. This is also suggested by studies on the formation of cobyrinic acid from [4-14C]5-aminolevulinate via uroporphyrinogen III in the presence of the aminomethylbilinogen by cell-free extracts from Clostridium tetanomorphum.