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Results for “CHOROID PLEXUS”

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PubMed1979

The choroid plexus of the mature and aging rat: the choroidal epithelium.

The choroid plexus of mature and old rats has been examined by both scanning and transmission electron microscopy. It has been shown that the macrophages lying upon the ventricular surface of the choroid plexus have a close association with burr-like protrusions that extend from the apical surfaces of the choroidal epithelial cells. These protrusions have a dark cytoplasm filled with vesicles and tubules, and projecting from them are thin, shrunken microvilli. It is suggested that these protrusions are phagocytosed by the macrophages and that they are the source of some of the inclusions which become increasingly common within the cytoplasm of macrophages in older rats. The lateral surfaces of the choroidal epithelial cells have also been examined in the scanning electron microscope after exposure of the surfaces by dissection. In such preparations it is apparent that the elaborate interdigitations between adjacent cells are effected by irregular and vertically arranged folds confined to the basal portions of the lateral cell surfaces. Lastly, it has been shown that at the junction between the choroid plexus and the ependyma in the lateral ventricle, there are two modes of transition between the choroidal and ependymal epithelia. In one, typical choroidal and ependymal epithelial cells lie next to each other to produce a distinct and continuous bondary. In the other mode the boundary is also continuous, but there are modified ependymal cells present. These modified cells have short, relatively sparsely distributed microvilli and not more than one or two cilia.

Aging↗

PubMed2000

Diagnostic imaging of choroid plexus disease.

Disorders of the choroid plexus, a central nervous system structure, are rare, but can pose diagnostic difficulties. The purpose of this review is to illustrate the computed tomography and magnetic resonance imaging findings of a wide spectrum of lesions that affect the choroid plexus. The areas covered include (1) neoplasms (papilloma, leukaemia, meningioma, lymphoma and metastases); (2) infections (bacterial, fungal and viral); (3) cysts; (4) haemorrhage; (5) congenital abnormalities (Sturge-Weber syndrome, Klippel-Trenaunay-Weber syndrome and vascular malformations); and (6) non-infectious inflammatory disorders (xanthogranulomas, inflammatory pseudotumour, neurosarcoidosis, rheumatoid nodule and villous hypertrophy). Few of the patterns of choroid plexus involvement are specific for a particular pathological process. Guermazi, A. (2000) Clinical Radiology 55, 503-516.

Adolescent↗

PubMedDate not supplied

Histaminergic cells in the choroid plexus of rat.

The choroid plexus of the rat was examined immunocytochemically using both an antibody directed towards a histamine thyroglobulin conjugate as well as to histidine decarboxylase. Histamine- as well as histidine decarboxylase-immunoreactive cells were found within or in the vicinity of the plexus epithelium, with processes extending to the neighbouring epithelial cells or surrounding tissue, suggesting a specific function for histamine on the choroid plexus.

Animals↗

PubMed2000

Symptomatic bilateral xanthogranulomas of choroid plexus in a child.

Choroid plexus xanthogranulomas are uncommon lesions that occur almost exclusively in adults; most of them constitute incidental autopsy findings. A case of symptomatic bilateral xanthogranulomas of choroid plexus in a 6 year-old girl with progressive visual loss is reported. Theories on the pathogenesis of this entity are reviewed.

Brain Diseases↗

PubMedDate not supplied

[Lateral ventricle choroid plexus papillomas in infants].

Choroid plexus papillomas are rare intracranial tumours occurring most frequently in children. In the period 1983-1988 in the neurosurgery department 10 infants were treated for choroid plexus papillomas. Their age was from 4 weeks to 12 months. The diagnosis was based on the results of ultrasonography and CT. Eight patients had shunts implanted for hydrocephalus. In most cases the histological examination demonstrated benign tumours. Radical removal of the lesion was done in 90% of cases, but, despite this, remote results were satisfactory in only 40% of cases.

Brain Neoplasms↗

PubMed1977

The effects of morphine on the accumulation of homovanillic and 5-hydroxyindoleacetic acids in the choroid plexus of rats.

1 Choroid plexus obtained from the lateral ventricles of the rat actively accumulated homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA). 2 Morphine 5 X 10(-6) M to 5 X 10(-4)M potentiated 5-HIAA accumulation but did not affect HVA accumulation. Levorphanol and dextorphan had little effect. 3 Naloxone at high concentrations inhibited both HVA and 5-HIAA accumulation. 4 Glutamic acid, glycine, and arginine also decreased 5-HIAA accumulation, but lysine, tryptophan, and aspartic acid had no effect. 5 Probenecid, naloxone, arginine, glycine, and tryptophan blocked the increase of 5-HIAA accumulation induced by morphine. 6 Acute or chronic morphine treatment did not increase the accumulation of 5-HIAA. 7 These results suggest that the increase of 5-HIAA or HVA in brain by morphine is not due to the inhibition of the elimination of these metabolites from the choroid plexus.

Amino Acids↗

PubMedDate not supplied

Choroid plexus cysts.

BACKGROUND: Research shows that there is an association between choroid plexus cysts and aneuploidy. Family physicians treating prenatal patients should understand the management of this sonographic finding. OBJECTIVE: To determine the epidemiology, pathophysiology, and management of prenatal choroid plexus cysts. CASE REPORT: A 23-year-old patient, gravida 1, para 0, was seen at an inner city Family Medicine health center for prenatal care. A screening ultrasonogram performed at 16 weeks of gestation showed bilateral choroid plexus cysts approximately 5 mm in diameter. The patient declined amniocentesis. Maternal serum triple screen markers (maternal serum alpha-fetoprotein, human chorionic gonadotropin, and estriol) were all normal, as was the level II sonogram at 20 weeks and the fetal echocardiogram at 28 weeks. At birth the baby was found to be normal after a clinical assessment was performed. METHODS: A review of the literature using MEDLINE with the search strategy of choroid plexus, choroid plexus fetus/fetal, choroid plexus management, choroid plexus treatment, and choroid plexus epidemiology.

Choroid Plexus↗

PubMed1975

[Histochemical correlations of vascular permeability and enzyme activity in the choroid plexus in man].

The choroid plexuses are characterized by the absence of alcaline phosphatase activity as well as the absence of any vascular barrier for proteins as revealed by fluorescein tracer observation. This correlation is interpreted as supporting the hypothesis of enzymatic control, via alcaline phosphatase, of the blood-brain barrier. Adenosine mono and triphosphatase activity, on the contrary, is identical in choroid plexus vessels and in vessels where the blood-brain barrier phenomena may be demonstrated.

Adenosine Triphosphatases↗

PubMed1991

Comprehensive lectin histochemistry of normal and neoplastic human choroid plexus cells: alternation of lectin-binding patterns through neoplastic transformation.

Lectin histochemistry of the normal and neoplastic human choroid plexus cells [six choroid plexus papillomas (CPPs) and three choroid plexus carcinomas (CPCs)] was performed using eight representative lectins to study the development of sugar chain structures and also to determine whether lectins were useful for a histopathological diagnosis of choroid plexus neoplasms (CPNs). The normal choroid plexus cells reacted with Ricinus communis (RCA-I). Canavalia ensiformis (Con A), Limax flavus (LFA) and Triticum vulgaris (WGA), while Arachis hypoaea (PNA) stained them only after the removal of sialic acid. Human fetal choroid plexus cells at 8 weeks gestation already showed the same lectin-binding patterns as adult ones. All CPNs were stained by RCA-I and Con A in a similar manner as the normal choroid plexus cells. Although seven CPNs were positive for LFA, two CPCs were not stained by LFA, which bound to sialic acid. Two LFA-positive CPPs were stained by PNA before the removal of sialic acid. Moreover, unlike the normal choroid plexus cells, Ulex europaeus-, Glycine maximus- and Dolichos biflorus-binding sites often appeared, and WGA-binding sites of three CPNs remained even after sialic acid removal. In conclusion, the glycosialylation in normal choroid plexus cells was completed during the early embryonic stage. The lectin-binding patterns of CPNs were heterogenous in each case. The alternation of the glycosialylation and/or acquisition of binding sites for some lectins was sometimes observed through a neoplastic transformation.

Adult↗

PubMed2003

Isolation of a set of genes expressed in the choroid plexus of the mouse using suppression subtractive hybridization.

The choroid plexus produces cerebrospinal fluid, providing a specialized environment for the CNS. We previously demonstrated that choroid plexus ependymal cells can enhance nerve regeneration in vivo and promote neurite outgrowth in vitro. To understand the molecular mechanisms of choroid plexus functions, we isolated genes predominantly expressed in the mouse choroid plexus using suppression subtractive hybridization. Out of the 49 complementary DNA (cDNA) fragments isolated in two types of screening, 43 matched known sequences in the database and six were novel. In one type of screening where choroid plexus cDNAs were subtracted with cerebral cortex cDNAs, transthyretin and phosphodiesterase I alpha were predominant. This is consistent with previous reports and supports the authenticity of our approach. In the other type of screening, cDNAs derived from the choroid plexus of neonatal (postnatal day 5) mice were subtracted with cDNAs from the choroid plexus of adult mice. RNA blot and/or in situ hybridization confirmed abundant expression, in the mouse choroid plexus, of the mRNA encoding gelsolin, phospholipid transfer protein, ATP-binding cassette transporter A8 (ABCA8), androgen-inducible aldehyde reductase, and Na(+)/sulfate cotransporter SUT-1. Also, one novel gene (FS88) was found to be expressed in the choroid plexus from neonatal mice. Our data suggest that the choroid plexus cells produce molecules involved in processes such as prevention of fibrillization of amyloid beta-protein (transthyretin and gelsolin), lipid metabolism (phospholipid transfer protein and ABCA8), and detoxification (androgen-inducible aldehyde reductase).

Animals↗

PubMed1998

Papillomas and carcinomas of the choroid plexus in children.

OBJECT: Choroid plexus tumors are rare intraventricular tumors (1% of all intracranial tumors) that occur mainly in children. The pathophysiological characteristics of associated hydrocephalus, surgical management, and oncological issues related to these tumors remain a matter of debate. To understand more about these tumors, the authors have reviewed their experience with the management of 38 children with choroid plexus tumors. METHODS: There were 25 cases of papilloma and 13 of carcinoma. The mean age of the patients at presentation was 22.5 months, and one-half of the patients were younger than 2 years of age. Hydrocephalus was present in 33 patients and poorly correlated with the size, site, and pathological characteristics of the tumor. In nine children, a ventriculoperitoneal shunt was required after tumor excision, calling into question the notion that cerebrospinal fluid oversecretion is the only cause of hydrocephalus. Complete excision was achieved in 96% of the cases of papilloma and 61.5% of the cases of carcinoma. These surgical procedures were complicated by the risks of intraoperative hemorrhage, which proved to be fatal in two cases, and postoperative brain collapse, which led to subdural fluid collections requiring subdural shunt placement in six patients. Preoperative embolization was partially successful in four cases and significantly assisted surgery. Preoperative controlled drainage of excessively dilated ventricles and intraoperative gluing of the cortical incision have been used to address the problem of postoperative brain collapse. Patients with carcinomas were treated postoperatively by chemotherapy alone (seven cases), radiotherapy (one case), or chemotherapy plus radiotherapy (one case). The overall 5-year survival rate was 100% for patients with papillomas and 40% for those with carcinomas. CONCLUSIONS: Total surgical excision is curative in cases of papillomas. For carcinomas, the most effective treatment remains total surgical excision; however, adjuvant treatment in the form of chemotherapy in patients younger than age 3 years, supplemented by radiation therapy in older children, can moderately reduce the risk of recurrence.

Adolescent↗

PubMedDate not supplied

Choroid plexus tumors in infants.

Choroid plexus tumors continue to be a challenge in their diagnosis, treatment, and associated conditions that occur in perioperative management. Improved radiographic techniques have recently aided surgical planning, and recent developments in operating room technology are having an impact on the favorable outcome of these patients. Cerebrospinal fluid dynamics often add to the complexity of the perioperative management.

Carcinoma↗

PubMed1993

Choroid plexus cysts in the fetal brain.

Choroid plexus cysts may be detected in the fetal choroid plexus on routine second trimester ultrasound scanning. The presence of these cysts is associated with trisomy 18 (Edward syndrome) in 3.47% of cases and with trisomy 21 (Down syndrome) in 0.46% of cases. The cysts themselves almost always disappear by 23 weeks and are thought to be a normal developmental variant. The world literature experience would indicate that the size of the choroid plexus cyst and the presence of bilateral cysts has no bearing on the magnitude of risk of chromosomal abnormality; 76% of babies with trisomy 18 also have other dysmorphic features which may be detectable by ultrasound. It is strongly advised that genetic counselling be undertaken and amniocentesis be considered when choroid plexus cysts are identified in the fetus.

Adult↗

PubMed2001

Mechanisms of CSF secretion by the choroid plexus.

The epithelial cells of the choroid plexus secrete cerebrospinal fluid (CSF), by a process that involves the movement of Na(+), Cl(-) and HCO(3)(-) from the blood to the ventricles of the brain. This creates the osmotic gradient, which drives the secretion of H(2)O. The unidirectional movement of the ions is achieved due to the polarity of the epithelium, i.e., the ion transport proteins in the blood-facing (basolateral) are different to those in the ventricular (apical) membranes. Saito and Wright (1983) proposed a model for secretion by the amphibian choroid plexus, in which secretion was dependent on activity of HCO(3)(-) channels in the apical membrane. The patch clamp method has now been used to study the ion channels expressed in rat choroid plexus. Two potassium channels have been observed that have a role in maintaining the membrane potential of the epithelial cell, and in regulating the transport of K(+) across the epithelium. An inward-rectifying anion channel has also been identified, which is closely related to ClC-2 channels, and has a significant HCO(3)(-) permeability. This channel is expressed in the apical membrane of the epithelium where it may play an important role in CSF secretion. A model of CSF secretion by the mammalian choroid plexus is proposed that accommodates these channels and other data on the expression of transport proteins in the choroid plexus.

Animals↗

PubMed1991

[Choroid plexus tumors in infancy].

Twelve infants with choroid plexus tumors were reviewed retrospectively. Enlarging head circumference, bulging fontanelle, and vomiting were the major symptoms and signs appearing 2 to 5 weeks (mean = 3.7 weeks) before diagnosis. The average age at diagnosis was 7.7 months. Total removal was performed in 11 patients with choroid plexus papilloma, and partial removal was achieved in 1 patient with a choroid plexus carcinoma. A cerebrospinal fluid (CSF) diversionary shunt was placed temporarily in 6 infants and permanently in 4. Of the two patients not requiring CSF diversionary shunt, 1 needed a subdural-peritoneal shunt postoperatively. Histologically, 11 of 12 tumors were choroid plexus papillomas, and one was a choroid plexus carcinoma. All 12 patients were followed up for 4 months to 11 years (mean = 5.6 years). Eleven of 12 patients were alive at the time of their last check-up. All 11 survivors had normal psychomotor and neurological development. The treatment and outcome of choroid plexus tumors and management of associated hydrocephalus are discussed.

Carcinoma↗

PubMed1988

An ultrastructural study of the choroid plexus of aged mice.

The choroid plexus of mice aged 25, 28 and 31 months was examined in the transmission electron microscope. The main changes noted with age were the presence of lipid droplets, dense bodies and, much more rarely, vacuoles surrounded by a fine lamellar membrane. The cytoplasm of light choroid epithelial cells seemed more electron-dense than in young adults and the microvilli were long and slender in contrast with the short, spatulate microvilli seen in young mice. Glycogen was rarely present in choroid plexus cells in old age. The morphological changes suggest a decrease in efficiency of choroid plexus epithelial cells in old age.

Aging↗

PubMed1989

Choroid plexus carcinoma in a dog.

Choroid plexus carcinoma was diagnosed in a 5-year-old female mixed breed dog which was euthanized due to progressive neurologic disease. Diagnosis of the tumour was based on gross and light microscopic findings following a complete necropsy. The chemical staining patterns in the case are compared with human choroid plexus tumours. The criteria for the distinction between benign and malignant variants of choroid plexus tumours are discussed.

Animals↗

PubMed1977

Disseminated choroid plexus papilloma. An ultrastructural study.

Choroid plexus papilloma is a rare intracerebral neoplasm that occasionally disseminates along the neuraxis. The fine structure of such a metastatic papilloma appears to correspond very closely to that of normal choroid plexus. Lack of capillary endothelial pores is the only meaningful difference. There does not appear to be an ultrastructural feature that is unique to disseminating choroid plexus papilloma.

Cell Membrane↗