Specificities of Meningitis and Meningo-Encephalitis After Kidney Transplantation: A French Retrospective Cohort Study.

Kidney transplant recipients develop atypical infections in their epidemiology, presentation and outcome. Among these, meningitis and meningoencephalitis require urgent and adapted anti-infectious therapy, but published data is scarce in KTRs. The aim of this study was to describe their epidemiology, presentation and outcome, in order to improve their diagnostic and management. We performed a retrospective, multicentric cohort study in 15 French hospitals that included all 199 cases of M/ME in KTRs between 2007 and 2018 (0.9 case per 1,000 KTRs annually). Epidemiology was different from that in the general population: 20% were due to Cryptococcus neoformans, 13.5% to varicella-zoster virus, 5.5% to Mycobacterium tuberculosis, and 4.5% to Enterobacteria (half of which produced extended spectrum beta-lactamases), and 5% were Post Transplant Lymphoproliferative Disorders. Microorganisms causing M/ME in the general population were infrequent (2%, for Streptococcus pneumoniae) or absent (Neisseria meningitidis). M/ME caused by Enterobacteria, Staphylococci or filamentous fungi were associated with high and early mortality (50%-70% at 1 year). Graft survival was not associated with the etiology of M/ME, nor was impacted by immunosuppression reduction. Based on these results, we suggest international studies to adapt guidelines in order to improve the diagnosis and the probabilistic treatment of M/ME in SOTRs.

Hospital burden of vertebral fractures in France: influence of vertebroplasty.

UNLABELLED: We described the whole population of patients hospitalized for vertebral fractures in France in 2009. Only 6.4 % of them were operated by vertebroplasty; these patients were younger and healthier than non-operated patients. INTRODUCTION: This study aims to describe the burden of vertebral fractures from the 2009 French Hospital National Database in acute care in people aged 60 years and over, with or without vertebroplasty. METHODS: All stays due to nonmalignant and nontraumatic vertebral fractures as primary cause were selected. Patients' characteristics were described and compared between patients with or without vertebroplasty. The in-patient mortality was compared to the one related to hip and upper humerus fracture in patients hospitalized during the same year. RESULTS: In 2009, 13,624 patients were hospitalized for vertebral fracture. Men accounted for 29.3 % of cases. Length of stay was 9.6 ± 8.2 days, higher in patients with at least one comorbidity than in patients without (11.2 ± 8.6 and 7.8 ± 7.2 days, respectively). The in-patient mortality was 0.9 %; it was 3.8 and 1.1 % for hip and upper humerus fractures, respectively. Vertebroplasty was performed in 6.4 % of them. Patients with vertebroplasty were younger (mean age of 75 ± 8 versus 79 ± 9 years), had a less duration of stay (7 ± 7.5 versus 9.8 ± 8.2 days), less comorbidities (at least one comorbidity, 45 versus 54 %), and less in-patient mortality (0.1 versus 0.9 %). Rehospitalization for vertebral fracture occurred in 9 and 6 % of the patient with and without vertebroplasty. CONCLUSION: This is the first French study assessing the national burden of vertebral fractures based on hospital data. In-hospital death rate is lower in patients with vertebroplasty, who are younger and have less comorbidities than the general population with vertebral fractures.

Change in hip fracture incidence over the last 6 years in France.

UNLABELLED: Controversies exist about the change in hip fracture incidence among countries. In France, over the last 6 years, the incidence in people aged 40 years and over of hip fractures decreased in women over 39 years and increased in men; a decrease in the incidence was observed in both genders in the elderly. INTRODUCTION: Controversies exist about the change in hip fracture incidence among countries. The aim of this study was to assess the incidence of hip fractures in men and women aged 40 years and over between 2002 and 2008 in France. METHODS: Data were drawn from the French Hospital National Database. The absolute number of admissions was described and the incidence rates per 1,000,000 adjusted on age (40-59, 60-74; 74-84, and ≥ 85 years), and gender was calculated using the data of the French population. RESULTS: The number of hip fractures increased in men (+13%; from 14,736 in 2002 to 16,611 in 2008) and remained stable in women (+0.2%, 50,910 in 2008). Between 2002 and 2008, the French population increased by 9% in both genders. Incidence over 39 years decreased by 8% in women (3,356 and 3,093 per million in 2002 and 2008, respectively) and increased by 4% in men (1,131 and 1,172 per millions in 2002 and 2008, respectively). An age-specific incidence decrease was found, in particular, in the elderly in both genders (74-84 and ≥ 85 years), most importantly in women. CONCLUSION: Over the last 6 years, the incidence of hip fractures decreased in women aged over 39 years and increased in men aged over 39 years; a decrease in the incidence of these fractures was observed in both genders in the elderly. Such epidemiological data may help policy making, planning resource allocation, and setting up complementary health decisions for the management of osteoporosis.

FGF-2-responsive neural stem cell proliferation requires CCg, a novel autocrine/paracrine cofactor.

We have purified and characterized a factor, from the conditioned medium of neural stem cell cultures, which is required for fibroblast growth factor 2's (FGF-2) mitogenic activity on neural stem cells. This autocrine/paracrine cofactor is a glycosylated form of cystatin C (CCg), whose N-glycosylation is required for its activity. We further demonstrated that, both in vitro and in vivo, neural stem cells undergoing cell division are immunopositive for cystatin C. Finally, we showed in vivo functional activity of CCg by demonstrating that the combined delivery of FGF-2 and CCg to the adult dentate gyrus stimulated neurogenesis. We propose that the process of neurogenesis is controlled by the cooperation between trophic factors and autocrine/paracrine cofactors, of which CCg is a prototype.

[Exercise alveolar hypoventilation in long-term survivors of bronchopulmonary dysplasia]. / Hypoventilation alvéolaire à l'exercice chez des enfants avec dysplasie bronchopulmonaire.

BACKGROUND: We aimed to confirm that children who have survived bronchopulmonary dysplasia (BPD) display lower ventilation during exercise than healthy children, and to determine whether alveolar hypoventilation associated with exercise-induced hypoxemia occurred in these children. METHODS: Twenty children with BPD (birth weight 1441+/-523 g [mean +/- SD], gestational age 31+2.3 weeks), aged 7 to 14 years, and 18 matched healthy children, born at term, performed resting pulmonary function and cardiopulmonary incremental exercise tests. Arterialized capillary blood gases were measured at rest and at maximal exercise in the BPD group. RESULTS: The BPD group showed moderate expiratory airflow limitation and hyperinflation. Maximal oxygen uptake and ventilatory threshold were similar in the two groups. The BPD group displayed ventilatory limitation on exercise, with greater use of the ventilatory reserve (p<0.01), lower maximal ventilation (p<0.01), tidal volume (p=0.01). Changes in ventilation (p<0.0001) and tidal volume (p=0.003) during exercise were significantly smaller in the BPD group than in controls, at similar submaximal workloads. At peak exercise, we observed hypoxemia in 12 BPD children (60%). In the subgroup with hypoxemia, a significant increase in PaCO2 (p=0.01) was measured at peak exercise, showing alveolar hypoventilation sustained by the lower tidal volume. CONCLUSIONS: Despite normal maximal aerobic performance, BPD children showed ventilatory limitation on exercise, frequently with hypoxemia and alveolar hypoventilation. Despite an improvement in their pulmonary condition, continued follow-up by cardiopulmonary exercise testing, is strongly recommended.

[Thyroiditis and gluten intolerance: extrapancreatic auto-immune diseases associated with type 1 diabetes]. / Thyroïdite et intolérance au gluten: maladies auto-immmunes extrapancréatiques associées au diabète de type 1.

OBJECTIVES: This study aimed at evaluating the screening of thyroïditis and coeliac disease, in a population of children and adolescents with type 1 diabetes, and at comparing the appearance of antibodies specific for these 2 diseases as a function of age. PATIENTS AND METHODS: The study included 370 children and adolescents, 179 girls and 191 boys, aged 13.8 +/- 4.4 yr and with diabetes for 7.1 +/- 3.8 yr. Auto-immune thyroïditis was screened using antimicrosomal and antithyroglobulin auto-antibodies, at a mean rhythm of 3 tests per patient (1 every 2 yr), associated with dosages of TSH and FT4. Coeliac disease was screened using antigliadin (+/- antiendomysium) auto-antibodies, at a mean rhythm of 2 tests per patient, and was confirmed by duodenojejunal biopsy. Antithyroïd auto-antibodies were correlated with age following the "censured data analysis" type approach. RESULTS: Antithyroïd autoantibodies were found in 42 patients (11.4%), of whom 9 were treated for hypothyroïdism and 1 for Basedow disease, and coeliac disease autoantibodies were found in 9 patients (3.2% of tested patients). The cumulated frequency of antithyroïd auto-antibodies increased regularly with age and was significantly higher in girls, reaching 28% in girls and 12% in boys around 18 yr of age. As a consequence of this evolution, antithyroïd auto-antibodies were frequently found at the time of diagnosis of diabetes when it declared after 10 yr of age, while they often became positive secondarily when diabetes occurred before 10 yr of age. Coeliac disease specific auto-antibodies appeared much earlier and were found at the time of diagnosis of diabetes or at the first screening test. CONCLUSION: Antithyroïd autoantibodies are increasingly frequent with age in children with type 1 diabetes, and become very elevated in girls. The rhythm for screening should be adapted to this evolution of autoantibodies with age, which is very different between thyroïditis and coeliac disease.

The growing teratoma syndrome: results of therapy and long-term follow-up of 33 patients.

Growing teratoma syndrome (GTS) is defined as an increase in tumour size during or after chemotherapy for germ cell tumour (GCT), and only mature teratoma at histological analysis of the resected tumour specimen. Between 1985 and 1997, 30 male patients fulfilling GTS criteria were included in the present study. 3 female patients were also included but analysed separately. A mature teratoma component was found in 86% of the primary GCT. 3 male patients (10%) had a complication at diagnosis of GTS. One male patient (4%) having undergone complete resection (n=24) had a recurrent GTS, compared with all but 1 patient (83%) in whom resection was partial (n=6) (P<0.001). 2 (8%) and 3 (50%) male patients treated with complete and partial resection subsequently developed a malignant NSGCT respectively (P=0.01). 2 female patients treated with partial resection presented a recurrent GTS. One of them died of this recurrent GTS. GTS is an entity in its own right with respect to complications and the natural history of the disease. Complete surgical resection is the treatment of choice for GTS.

A fraction enriched in rat hippocampal mossy fibre synaptosomes contains trophic activities.

Subcellular fractions prepared from the rat hippocampus, were assessed for the presence of trophic activities. The cytosol of synaptosomal fractions induced mitotic reinitiation of confluent 3T3 fibroblasts. The synaptosomal fraction, enriched in mossy fibre terminals, contained the highest mitotic activity. The mitogenic activity was heat and trypsin sensitive, suggesting that polypeptides are involved. The cytosol of the mossy fibre synaptosomal fraction promoted neuritic outgrowth of PC 12 cells and embryonic hippocampal neurones in primary cultures. These results suggest that mossy fibres contain both mitogenic and neurotrophic activities. These factors could participate in mossy fibre sprouting that occur following brief seizures or experimental lesions.

Subcellular fractionation on Percoll gradient of mossy fiber synaptosomes: evoked release of glutamate, GABA, aspartate and glutamate decarboxylase activity in control and degranulated rat hippocampus.

Using discontinuous density gradient centrifugation in isotonic Percoll sucrose, we have characterized two subcellular fractions (PII and PIII) enriched in mossy fiber synaptosomes and two others (SII and SIII) enriched in small synaptosomes. These synaptosomal fractions were compared with those obtained from adult hippocampus irradiated at neonatal stage to destroy granule cells and their mossy fibers. Synaptosomes were viable as judged by their ability to release aspartate, glutamate and GABA upon K+ depolarization. After irradiation, compared to the control values, the release of glutamate and GABA was decreased by 57 and 74% in the PIII fraction, but not in the other fractions and the content of glutamate, aspartate and GABA was also decreased in PIII fraction by 62, 44 and 52% respectively. These results suggest that mossy fiber (MF) synaptosomes contain and release glutamate and GABA. Measurement of the GABA synthesizing enzyme, glutamate decarboxylase, exhibited no significant difference after irradiation, suggesting that GABA is not synthesized by this enzyme in mossy fibers.

Efficacy and tolerability of acetazolamide in migraine prophylaxis: a randomised placebo-controlled trial.

BACKGROUND: Familial hemiplegic migraine and episodic ataxia type 2 (EA2) are allelic disorders with distinct types of mutations in the CACNA1A gene. EA2 attacks are remarkably sensitive to acetazolamide, a carbonic anhydrase inhibitor. The effectiveness of acetazolamide in migraine prophylaxis is unknown. OBJECTIVES: To evaluate the efficacy and the tolerability of acetazolamide in migraine prophylaxis. METHODS: We compared daily oral 500 mg acetazolamide and placebo in patients with migraine in a multicentre, double-blind, randomised trial of 12 weeks duration after a run-in period of 4 weeks without treatment. Frequency of attacks at the last trial period of 4 weeks was the primary efficacy criterion. Secondary efficacy criteria were the frequency of attacks per 4 weeks, the severity and duration of attacks, the number of hours with migraine as well as the number of responders with more than 50% reduction in attack frequency. RESULTS: 53 patients had been enrolled when the study was prematurely stopped because of a high number of withdrawals (34%), primarily linked to acetazolamide related side effects. Considering the primary and secondary efficacy criteria, among the 53 included patients (27 in the placebo group and 26 in the acetazolamide group), no difference between the 2 study groups could be demonstrated. The most frequent adverse events related to acetazolamide were paresthesias and asthenia. CONCLUSIONS: In this trial, migraine sufferers poorly tolerated acetazolamide given in an oral dose of 500 mg daily. No obvious prophylactic beneficial effect of acetazolamide appeared on migraine attacks.

Heterogeneity of fetal growth in type 1 diabetic pregnancy.

OBJECTIVE: To investigate the frequency of macrosomia in an homogeneous cohort of type 1 diabetic mothers and to analyze the influence of maternal factors and glycemic control on the incidence of fetal macrosomia. MATERIAL AND METHODS: Fifty-five consecutive type 1 diabetic first-pregnancies were prospectively studied. Macrosomia was defined by a ponderal index above the 90(th) percentile. Venous cord blood levels of insulin, C peptide and leptin were measured at delivery. The influence of HbA1c levels and other maternal variables on the occurrence of macrosomia and on the ponderal index was assessed using a stepwise regression logistic model. RESULTS: The mean (+/- SD) birth weight was 3482 (+/- 497) g at 37.4 +/- 1.0 weeks gestation. Macrosomia occurred in 29 cases (53.7%). Fetal insulin, C peptide and leptin levels were significantly higher in macrosomic than in non macrosomic infants. Maternal age, duration of diabetes, pregravid body mass index, parity, weight gain during pregnancy, presence of a microangiopathy, nephropathy, smoking habits, gestational hypertension or preeclampsia, and HbA1c levels throughout pregnancy did not differed between mothers of macrosomic and non macrosomic infants. In the stepwise analysis none of these covariates was explanatory of the ponderal index. CONCLUSIONS: The frequency of macrosomia remains very high in infants of type 1 diabetic mothers despite a reasonable degree of glycemic control. The variability of the fetal growth response to mild hyperglycemia prompts for the identification of other factors involved in the modulation of fetal growth.

Subchronic toxicity study in rats fed gum karaya.

Gum karaya was given to groups of 15 rats of each sex at levels of 0 (control), 0.2, 1 or 5% (w/w) in the diet for 13 wk. An increase in faecal bulk was seen in all treated groups throughout the study. There was a decrease in weight-gain at the highest dietary level (significant only in the females), which was associated with a marginal reduction in food-conversion efficiency. Males given 1 or 5% drank more than the controls and a transient increase in water intake was seen in females given the highest level. The no-untoward-effect level from this study was 5% (w/w) of the diet, providing a mean intake of about 4 g karaya gum/kg body weight/day.

[A comparative study of body temperature using rectal and tympanic measurement]. / Etude comparative de la température corporelle par mesure rectale et tympanique.

INTRODUCTION: Tympanic temperature measuring is more and more used currently. We wanted to test this method's accuracy in an internal medicine service. METHODS: First, we compared rectal and tympanic temperatures in 37 consecutive patients. Tympanic temperature was assessed by two examiners. Secondly, we compared, in 32 other patients, the readings given by tympanic thermometer used in the first part, with those given by nine other tympanic thermometers used in other hospital departments. RESULTS: We did not find any difference between right and left auricular temperature, nor between the temperatures assessed by the two examiners. However, there was a difference between the average tympanic and rectal temperatures (36.88 degrees C +/- 0.63 vs 37.36 degrees C +/- 0.57; P < 0.001). The correlation coefficient between tympanic and rectal temperature was only 0.77. If a threshold of temperature of > or = 38 degrees C were given for fever, only 29% of febrile patients would have been detected with a tympanic thermometer (Kappa coefficient = 0.406 [0.326-0.485]). Fever was especially underestimated for high temperatures. The comparison of different tympanic thermometers gives different averages for these ten thermometers between 36.5 degrees C and 37.2 degrees C. CONCLUSION: Though tympanic temperature measure is an easy method, it is not sensitive enough to detect fever.

[Incidence of end-stage renal disease in Ile de France: a prospective epidemiological survey]. / Incidence de l'insuffisance rénale terminale en Ile de France: enquête épidémiologique prospective.

OBJECTIVES: To evaluate incidence and prevalence of patients with end-stage renal disease (ESRD) treated with maintenance dialysis in the Ile de France district in 1998. METHODOLOGY: Prospective epidemiologic inquiry with the cooperation of the 91 nephrology departments and dialysis facilities of the Ile de France district (total population: 10,695,300 inhabitants in March 1999), from January 1st to December 31st, 1998. Evaluation of the demographic and clinical characteristics of the 1155 patients accepted on maintenance dialysis in 1998, and recording of the total number of dialyzed patients at the beginning and at the end of the same year. RESULTS: The total number of ESRD patients was 1155, including 29 (2.5%) children aged < or = 17 years and 86 (7.4%) returns to dialysis following kidney graft failure. Incidence of ESRD in first-dialyzed patients was 100/million/year and overall incidence, including returns from transplantation, was 108/million/year. Mean age of the 1040 adult first-dialysis patients was 59 +/- 16.8 years, with a proportion of those aged > or = 75 years of 21.6%. Patients with vascular renal disease were 22.5% and those with diabetic nephropathy 20.6%. As a whole, 36.5% of patients were referred to the nephrologist < 6 months of starting dialysis. Prevalence of patients on supportive dialysis increased from 417 to 433 per million inhabitants (a 3.8% increase) from the beginning to the end of 1998, with the proportion of patients treated with self-care dialysis or peritoneal dialysis rising by 10%. From January 1995 to January 1999, prevalence of dialysis-treated ESRD patients rose by nearly 4% per year as a mean. CONCLUSION: Incidence of ESRD patients requiring maintenance dialysis in the Ile de France district reached 100/million in 1998, an increment of 4% per year over the past 4 years. The increase in incidence results from the increasing number of older patients, parallel to the ageing of general population, these patients having a high comorbidity mainly due to diabetes and atherosclerosis. Prevalence of dialysis-treated patients was 433/million population at the end of 1998. It rose at a similar rate as did incidence, although with a growing proportion of out-center dialysis.

[Dirofilariasis in France: a case in Languedoc in an HIV-seropositive patient]. / La dirofilariose en France: un cas languedocien chez un sujet sérologiquement positif pour le VIH.

Dirofilaria repens is an endemic canine parasite in the Mediterranean area. Human infestation is rare. We observed a case in an HIV-positive patient who presented an ocular filaria which was successfully removed under local anesthesia. In man, filariae may be expulsed without a parasite cycle or complete a growth cycle, depending on the individual's immunological status. The disease has been known in southern France for several centuries, mainly in lagoons near the Mediterranean seaside. A review of the literature however shows that observation of clinical cases is rare, only 46 cases having been reported to date. Outcome is favorable.

Effects on growth and metabolism of growth hormone treatment for 3 years in 36 children with Prader-Willi syndrome.

BACKGROUND/AIMS: Prader-Willi syndrome (PWS) is a complex genetic disorder whose many manifestations include obesity and short stature. Diabetes, osteoporosis, and scoliosis are common. We evaluated the effects of human growth hormone (hGH). METHODS: A prospective cohort study of 36 children (1-15 years of age) with genetically confirmed PWS who were given hGH (mean dose 0.033 ± 0.006 mg/kg/day) for 36 months. At baseline and once yearly, we evaluated growth, insulin-like growth factor-1 (IGF-1), body composition, bone mineral density (BMD), glucose tolerance, serum lipids, and spinal radiographs. RESULTS: Height gain over the 3-year period was 1.2 SD score. Lean body mass increased significantly during each treatment year. Total body fat decreased by 5.42 and 1.17% in the 1st and 2nd years, respectively. BMD remained unchanged during therapy. IGF-1 and homeostasis model assessment index of insulin resistance increased, and glucose intolerance was found in 22.7% of patients at baseline and 0% at 3 years. None of the patients had diabetes. Their lipid profile improved. Scoliosis was present in 27.8% of the patients at baseline and 47.2% at 3 years. CONCLUSION: GH treatment in children with PWS has multiple beneficial effects on growth and body composition. Tolerance is good, with an improvement in glucose metabolism, although IGF-1 levels and insulin resistance parameters should be monitored closely. The high rate of scoliosis warrants monitoring by a pediatric orthopedic surgeon.

Hospitalized wrist fractures in France: Incidence and burden trend changes.

INTRODUCTION: The aim of this study was to assess the burden of hospitalized wrist fractures between 2002 and 2006 in France. METHODS: Data were drawn from the French Hospital National Database. The number of admissions and the incidence rates were described as well as the type of entry and discharge from hospital, length of stay, and 2006 in-patients costs. RESULTS: In 2002 and 2006, 38,710 and 38,979 hospitalizations for wrist fractures were registered respectively. The incidence rate of fractures increased with age whatever the year and decreased significantly from 2002 to 2006. Length of stay and mean inpatients costs increased with age. The overall in-patients 2006 costs was 79 millions with an average individual cost of 2100 € per hospitalized wrist fractures. CONCLUSION: The incidence of hospitalizations for wrist fractures decreased in 2006 compared to 2002. The number of hospitalizations increased, as a consequence of ageing, (except for wrist fracture in men), with a subsequent increase in cost related to these fractures. The increase with age outlines the role of underlying osteoporosis and the relevance of appropriate care of patients at risk of for such fractures. LEVEL OF EVIDENCE: IV.

Potential of neural stem cells for the treatment of brain tumors.

Neural stem cells (NSCs) are self-renewing multipotent cells that generate the main phenotypes of the nervous system, neurons, astrocytes and oligodendrocytes. As such they hold the promise to treat a broad range of neurological diseases and injuries. Neural progenitor and stem cells have been isolated and characterized in vitro, from adult, fetal and post-mortem tissues, providing sources of material for cellular therapy. However, NSCs are still elusive cells and remain to be unequivocally identified and characterized, limiting their potential use for therapy. Neural progenitor and stem cells, isolated and cultured in vitro, can be genetically modified and when transplanted migrate to tumor sites in the brain. These intrinsic properties of neural progenitor and stem cells provide tremendous potential to bolster the translation of NSC research to therapy. It is proposed to combine gene therapy and cellular therapy to treat brain cancers. Hence, neural progenitor and stem cells provide new opportunities for the treatment of brain cancers.

A simple and direct pre-embedding technique for ultrastructure of scarce biological specimens.

A simple and rapid technique for pre-embedding scarce biological specimens for Transmission electron microscopy (TEM) is reported. It is based on pre-embedding biological samples in bovine serum albumin (BSA) and bis-acrylamide (BA), cross-linked and polymerized with paraformaldehyde, glutaraldehyde, ammonium persulfate and Temed. Pre-embedding in BSA and BA offers several advantages over traditional pre-embedding techniques for TEM including the ability to visualize the sample and a more resistant matrix. This results in more reproducible and consistent analysis. It can be applied to tissues, cells, and subcellular structures handled as pellets or suspensions. In addition, use of the pre-embedding matrix for light microscopy is reported. The ability to pre-embed scarce biological specimens efficiently and reproducibly provides a valuable way to study and characterize cytological tissues such as biopsies or cystic and amniotic fluid cells.

Subcellular fractionation on Percoll gradient of mossy fiber synaptosomes: morphological and biochemical characterization in control and degranulated rat hippocampus.

A method for preparation of hippocampal mossy fiber synaptosomes directly from the postnuclear pellet is presented. This method represents an adaptation of that previously described for the isolation of synaptosomes by centrifugation through Percoll gradients directly from the supernatant fraction. We have characterized by electron microscopy two fractions, PII and PIII, enriched in mossy fiber synaptosomes; fraction PIII had 75% mossy fiber synaptosomes with well-preserved morphology (large size 3 microns, complex morphology, high synaptic vesicle density, multisynapses), whereas fraction PII contained 12%. These fractions were enriched in lactate dehydrogenase activity indicating that the integrity of synaptosomes was preserved. Compared with the other synaptosomal fractions, these fractions showed greater levels of dynorphin A (1-8) immunoreactivity and endogenous zinc, which are particularly concentrated in hippocampal mossy fiber terminals. Furthermore, we prepared synaptosomes from adult hippocampus after neonatal irradiation, which destroys the majority of granule cells and associated mossy fibers. The levels of dynorphin and zinc decreased by 88 and 70% in fraction PII and by 95 and 90%, respectively, in PIII. These results suggest that the rapid Percoll procedure is convenient for the purification of mossy fiber synaptosomes.