Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Choroiditis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed2002

Photodynamic therapy for choroidal hemangioma associated with serous retinal detachment.

OBJECTIVE: To describe the clinical findings in 3 eyes with circumscribed choroidal hemangioma before and after treatment with photodynamic therapy. PATIENTS AND METHODS: In the setting of a tertiary referral center, 2 patients with circumscribed, posteriorly located, choroidal hemangiomas (thicknesses 2.4 and 2.9 mm) contiguous with the superior boundary of the optic nerve and accompanied by serous detachments of the sensory retina extending into the macula were treated with photodynamic therapy using a Zeiss diode laser (692 nm) and a sensitizing dye, verteporfin. A third patient with a circumscribed subfoveal hemangioma (3.9 mm in thickness) and a prominent serous retinal detachment was similarly treated. The tumors were studied with ultrasonography and fluorescein angiography. Visual fields were tested with Goldmann perimetry at follow-up. RESULTS: Following photodynamic therapy, the serous retinal detachments resolved, and the choroidal hemangioma in each of the 3 eyes regressed to a nonmeasurable thickness within 2 to 5 months. The visual acuity improved from 20/50 to 20/20, 20/150 to 20/20, and 3/200 to 20/200 in the respective cases. Two eyes were treated twice. The tumors have not recurred at follow-up visits from 11 to 16 months. Nerve fiber bundle field defects were not demonstrated with Goldmann field testing. CONCLUSIONS: Photodynamic therapy seems to be effective in the management of circumscribed choroidal hemangioma. Following photodynamic therapy, the choroidal hemangiomas in 3 eyes were no longer measurable by ultrasonography, and the accompanying serous detachments resolved with improvement in the central visual acuities. Nerve fiber bundle defects were not identified.

Aged↗
PubMed2004

Surgical removal vs observation for subfoveal choroidal neovascularization, either associated with the ocular histoplasmosis syndrome or idiopathic: I. Ophthalmic findings from a randomized clinical trial: Submacular Surgery Trials (SST) Group H Trial: SST Report No. 9.

OBJECTIVE: To present visual acuity findings and related outcomes from eyes of patients enrolled in a randomized trial conducted by the Submacular Surgery Trials (SST) Research Group (SST Group H Trial) to compare surgical removal vs observation of subfoveal choroidal neovascular lesions that were either idiopathic or associated with ocular histoplasmosis. METHODS: Eligible patients 18 years or older had subfoveal choroidal neovascularization (new or recurrent) that included a classic component on fluorescein angiography and best-corrected visual acuity of 20/50 to 20/800 in 1 eye ("study eye"). Patients were examined 3, 6, 12, and 24 months after enrollment to assess study outcomes and adverse events. Best-corrected visual acuity was measured by a masked examiner at the 24-month examination. A successful outcome was defined a priori as 24-month visual acuity better or no more than 1 line (7 letters) worse than at baseline. RESULTS: Among 225 patients enrolled (median visual acuity 20/100), 113 study eyes were assigned to observation and 112 to surgery. Forty-six percent of the eyes in the observation arm and 55% in the surgery arm had a successful outcome (success ratio, 1.18; 95% confidence interval, 0.89-1.56). Median visual acuity at the 24-month examination was 20/250 among eyes in the observation arm and 20/160 for eyes in the surgery arm. The prespecified subgroup of eyes with visual acuity worse than 20/100 at baseline (n = 92) had more successes with surgery; 31 (76%) of 41 eyes in the surgery arm vs 20 (50%) of 40 eyes in the observation arm examined at 24 months (success ratio, 1.53; 95% confidence interval, 1.08-2.16). Five (4%) of 111 eyes in the surgery arm subsequently had a rhegmatogenous retinal detachment. Twenty-seven (24%) of 112 initially phakic eyes in the surgery arm (none in the observation arm) had cataract surgery during follow-up, all among patients older than 50 years. Recurrent choroidal neovascularization developed by the 24-month examination in 58% of surgically treated eyes. CONCLUSIONS: Overall, findings supported no benefit or a smaller benefit to surgery than the trial was designed to detect. Findings support consideration of surgery for eyes with subfoveal choroidal neovascularization and best-corrected visual acuity worse than 20/100 that meet other eligibility criteria for the SST Group H Trial. Other factors that may influence the treatment decision include the risks of retinal detachment, cataract among older patients, and recurrent choroidal neovascularization and the possibility that additional treatment will be required after submacular surgery.

Adult↗
PubMed2005

Health- and vision-related quality of life among patients with ocular histoplasmosis or idiopathic choroidal neovascularization at enrollment in a randomized trial of submacular surgery: Submacular Surgery Trials Report No. 5.

OBJECTIVES: To (1) summarize vision-targeted and general health-related quality-of-life scores at baseline and quantify the effect of the ophthalmic problem, (2) evaluate the strength of relations between visual acuity and interview scores, and (3) compare scores for patients who also had choroidal neovascular lesions in the fellow eye (bilateral cases) with those of patients who had choroidal neovascularization in only the study eye (unilateral cases) at time of enrollment in a randomized trial of surgical removal of subfoveal choroidal neovascularization, either associated with the ocular histoplasmosis syndrome or of idiopathic origin. DESIGN: Eligible patients had subfoveal choroidal neovascularization (including some classic choroidal neovascularization) and a visual acuity of 20/50 to 20/800 (Snellen equivalent), inclusive, in the eye to be assigned randomly to surgery or observation. Interviews that incorporated the 39-item version of the National Eye Institute Visual Function Questionnaire (NEI-VFQ) and 2 other instruments were conducted by telephone by trained interviewers before patients enrolled and were assigned randomly to surgery or observation. Information from baseline clinical examinations and fluorescein angiograms interpreted centrally by masked readers was used to classify patients as unilateral or bilateral cases and to provide potential explanations for variability of interview responses using linear regression models. RESULTS: The median overall NEI-VFQ score was 75 (interquartile range, 60-84). The median scores on individual subscales ranged from 55 (general vision) to 100 (color vision). The visual acuity of the better-seeing eye accounted for much of the variability in scores on most NEI-VFQ subscales; a 3-line difference in visual acuity was associated with a 10-point or greater difference in scores on 5 subscales after adjustment for other characteristics of patients and eyes. Scores on most scales of all 3 instruments differed between unilateral cases (n = 167) and bilateral cases (n = 58). Even after adjustment for visual acuity and reading speed of the better-seeing eye, age, gender, and scores on the other instruments, scores on the NEI-VFQ near and distance activities subscales differed by almost 13 and 10 points, respectively, between unilateral and bilateral cases. Neither age nor gender was an important independent explanatory variable for NEI-VFQ scores. CONCLUSIONS: Unilateral and bilateral cases had vision-targeted health-related quality-of-life scores worse than those published for a reference population without eye disease. Furthermore, despite younger age, better visual acuity, and better short-term visual prognosis, bilateral cases had NEI-VFQ scores at baseline similar to those published for 2 groups of patients with age-related macular degeneration. Unidentified factors, in addition to the visual acuity of the better-seeing eye, affected patients' perceptions of visual function.

Adolescent↗
PubMed2005

Microsatellite instability and alterations of mismatch repair protein expression in choroidal melanomas.

OBJECTIVES: To examine choroidal melanomas for genomic instability, manifested by microsatellite instability (MSI) and mismatch repair (MMR) protein alterations, and to determine the association of these alterations with selected clinicopathological features of the tumors. METHODS: Polymerase chain reaction-based microsatellite assays were applied to analyze 57 cases of choroidal melanomas using 11 microsatellite markers at 5 chromosomal regions: 1p, 2p, 4q, 9p, and 17p. Immunoperoxidase staining methods and mouse monoclonal antibodies were used to investigate the expression patterns of MMR proteins. RESULTS: Microsatellite instability was found at the 1p, 9p, and 17p regions in these lesions with an overall prevalence of 35% (20/57). The frequency of MSI ranged from 9% (1/11) to 27% (3/11), ie, low-level MSI (MSI-L). The instability was most commonly found at the 1p region (D1S2734, 55%; D1S2832, 40%; and D1S233, 20%). Two MSI banding patterns, band shifts and the appearance of additional bands, were found in 10% and 90% of the unstable lesions, respectively. The average percentages of hMLH1 and hMSH2 positively stained cells were insignificantly reduced in the unstable lesions (81.7 +/- 9.3 and 76.7 +/- 16.7) as compared with the stable lesions (84.1 +/- 15.5 and 78.6 +/- 19.6; P = .62 and 0.74 for hMLH1 and hMSH2, respectively). There was no significant difference in survival between the 2 groups; however, relative to the stable subset, the unstable tumors showed a trend (P<.10) toward occurring at a younger age and having tumor cells in vascular lakes. CONCLUSIONS: The presence of MSI-L in some choroidal melanomas defines a novel genetic subset of these tumors and suggests that MSI (genomic instability) may play a role in their molecular pathogenesis. Elucidation of the underlying mechanisms for MSI will require further investigation. CLINICAL RELEVANCE: Detection of the MSI-L pattern might prove to be useful as an adjunct to the conventional diagnosis of choroidal melanomas. Larger series are needed to determine whether any of the correlative trends noted in this study will achieve statistical significance. To the best of our knowledge, this study is the first to define both the MSI and MMR protein expression features of choroidal melanomas.

Base Pair Mismatch↗
PubMed2005

Safety and efficacy of intravitreal injection of ranibizumab in combination with verteporfin PDT on experimental choroidal neovascularization in the monkey.

OBJECTIVE: To study the safety and efficacy of intravitreal injections of anti-vascular endothelial growth factor antibody fragment (ranibizumab [formerly known as rhuFabV2], Lucentis; Genentech, South San Francisco, Calif) in combination with intravenous verteporfin (Visudyne; Novartis, East Hanover, NJ) photodynamic therapy (PDT) on experimental choroidal neovascularization in the monkey eye. METHODS: Choroidal neovascularization was induced by laser injury in both eyes of cynomolgus monkeys and followed with weekly fundus photography and fluorescein angiography. Two weeks after induction, weekly treatments were initiated. These treatments included using either an intravitreal injection of ranibizumab (previously known as rhuFabV2) in combination with verteporfin PDT or a ranibizumab vehicle (placebo) in combination with verteporfin PDT (PDT only). Six animals (group 1) initially received intravitreal injections followed 1 week later by PDT. Four animals (group 2) initially received PDT followed 1 week later by intravitreal injection. Two animals (group 3) received injections and PDT on the same day at 2-week intervals. Photodynamic therapy was applied in all 3 groups every 2 weeks for 3 treatments with follow-up through 2 weeks after the last PDT treatment. Fluorescein angiograms were graded using a masked standardized protocol. The data were analyzed using the McNemar chi(2) test for matched pairs. RESULTS: No choroidal neovascularization leakage was observed in the eyes of animals treated with ranibizumab and PDT at day 21 or 42 after the start of the first treatment. Leakage persisted in eyes treated with PDT alone at 21 days (3 of 12 eyes) and 42 days (2 of 12 eyes). At all time points studied, the ranibizumab and PDT-treated eyes experienced better angiographic outcomes than the eyes receiving PDT alone. CONCLUSION: These preliminary data indicate that an intravitreal ranibizumab injection in combination with verteporfin PDT (ranibizumab and PDT) causes a greater reduction in angiographic leakage than PDT and intravitreal vehicle injection (PDT only) in experimental choroidal neovascularization. CLINICAL RELEVANCE: This combination therapy can potentially offer a new treatment modality for choroidal neovascularization in patients with macular degeneration and other diseases.

Animals↗
PubMed1977

Bilateral choroidal melanomas. Case report and incidence.

A 55-year-old woman had bilateral choroidal melanoma. To our knowledge, this is the second reported case in the United States. To calculate the incidence of bilateral cases, we determined the incidence of unilateral choroidal and ciliary body melanomas among the white population in Iowa. We also studied the incidence of these melanomas by different age and sex groups. One of 2,500 whites will develop a choroidal melanoma during his or her lifetime. Based on these values and those of life expectancy in patients harboring a choroidal melanoma, we calculated the risks of developing a second primary melanoma in the other eye. In a population of 50 million whites, 1 person will develop a bilateral choroidal melanoma during his or her lifetime. In other words, a bilateral case is expected to occur once every 18 years in the United States.

Age Factors↗
PubMed1995

Outcome of corneal grafting with donor tissue from eyes with primary choroidal melanomas. A retrospective cohort comparison.

OBJECTIVES: To determine if melanomas have occurred in the recipients of corneas from donor eyes with primary choroidal melanomas and to determine the success of corneal grafting with tissue taken from eyes with primary choroidal melanomas. DESIGN: Retrospective cohort comparison and follow-up patient questionnaire. SETTING: A tertiary medical center in Rochester, Minn. PATIENTS: In patients who received corneal transplants, we reviewed 47 consecutive corneas transplanted from donor eyes enucleated for choroidal melanomas and compared them with 47 corneal grafts from donor eyes without melanomas matched for recipient age (+/- 10 years), date of operation (+/- 12 months), corneal storage time (+/- 24 hours), and operation type. RESULTS: No melanomas occurred in either group over a mean follow-up of 5.4 years (range, 0.4 to 15 years). There was no significant difference between the two groups in corneal thickness and endothelial cell loss at 2 months and 1 year after transplantation and in the probability of a rejection episode. CONCLUSIONS: There is no evidence of tumor transmission by transplantation of corneas from donor eyes with primary choroidal melanomas. Corneas transplanted from donor eyes with primary choroidal melanomas have similar outcomes to corneas transplanted from donor eyes without melanomas.

Adult↗
PubMed1996

Diffuse choroidal melanoma. Clinical features predictive of metastasis.

OBJECTIVE: To assess the clinical features that predict metastasis of diffuse choroidal melanoma. DESIGN: A review of patients who had been diagnosed clinically as having diffuse choroidal melanoma evaluated on the Oncology Service at Wills Eye Hospital, Philadelphia, Pa. MAIN OUTCOME MEASURE: Effect on metastasis of clinical features of the tumor. RESULTS: Of 3500 consecutive patients with choroidal melanoma, 111 (3%) had diffuse choroidal melanoma. Of these 111 tumors, the mean tumor base was 14.7 mm and the mean overall tumor thickness was 2.1 mm. The thickness-to-base percentage averaged 14.8%. The tumor had poorly defined margins in 39 patients (35%), orange pigment on its surface in 49 (44%), and a secondary serous retinal detachment in 76 (68%). Optic nerve invasion was clinically suspected in 2 patients (2%) and transcleral extension in 3 (3%). Initial management was enucleation in 36 patients (32%), plaque radiotherapy in 60 (54%), laser photocoagulation in 3 (3%), and observation in 12 (11%). During a mean follow-up of 5.3 years (median, 3.9 years), metastasis developed in 29 patients (26%). Using Kaplan-Meier survival estimates, the probability of metastasis developing was 16% at 3 years, 24% at 5 years, and 36% at 10 years. The clinical factors predictive of metastasis by univariate analysis included tumor basal dimension 18 mm or more (P = .002), poorly defined tumor margins (P = .03), transcleral extension (P = .003), and optic nerve invasion (P = .03). The clinical factors predictive of metastasis by multivariate analysis included basal dimension of 18 mm or more (P = .01), optic nerve invasion (P = .03), and poorly defined tumor margins (P = .05). CONCLUSIONS: Despite its relative flatness, diffuse choroidal melanoma carries a metastatic potential of 24% at 5 years. The risks for metastasis are greatest with increasing tumor base and poorly defined margins. Recognition of the clinical features of this tumor in the earliest stage and prompt treatment are encouraged.

Adolescent↗
PubMed1996

Intravenous infusion of liposomal benzoporphyrin derivative for photodynamic therapy of experimental choroidal neovascularization.

OBJECTIVE: To compare the effectiveness of photodynamic therapy to close experimental choroidal neovascularization using an intravenous infusion of liposomal benzoporphyrin derivative (verteporfin) with previous work using a rapid intravenous injection, before initiating clinical trials. METHODS: Choroidal neovascularization was induced in cynomolgus monkey eyes using argon laser. Liposomal benzoporphyrin derivative was delivered by an intravenous infusion pump for 10 or 32 minutes at a dose of 0.375 mg/kg. Irradiation was performed with 689- or 692-nm laser light (600-mW/cm2 irradiance and 150-J/cm2 fluence) in 7 normal eyes and 11 eyes with choroidal neovascularization between 30 and 105 minutes after the start of dye infusion. Findings were documented by fundus photography, fluorescein angiography, and light and electron microscopy. RESULTS: Irradiation within 32 to 50 minutes of the start of the fast (10 minutes) or slow (32 minutes) dye infusion resulted in closure of choroidal neovascularization. In normal eyes, this technique caused choriocapillaris closure and retinal pigment epithelium damage with minimal damage to surrounding tissues. CONCLUSION: Photodynamic therapy using intravenous infusion of liposomal benzoporphyrin derivative selectively closed experimental choroidal neovascularization. This may be a suitable modality for clinical use.

Animals↗
PubMed1997

Factors predictive of growth and treatment of small choroidal melanoma: COMS Report No. 5. The Collaborative Ocular Melanoma Study Group.

OBJECTIVES: To describe time to tumor growth of a prospectively followed group of patients with small choroidal melanoma and to determine baseline clinical and photographic characteristics associated with time to growth. METHODS: The Collaborative Ocular Melanoma Study (COMS) is a set of clinical trials designed to compare radiotherapy and enucleation in the treatment of medium- and large-size choroidal melanoma. From December 1986 to August 1989, patients with small choroidal melanoma, not large enough to be eligible for the COMS clinical trials, were offered participation in a nonrandomized prospective follow-up study. Small choroidal melanomas were defined as 1.0 to 3.0 mm in apical height and 5.0 to 16.0 mm in largest basal dimension. A total of 204 patients were enrolled in the study and were followed up annually through August 1989. An assessment of current size of tumor, treatment status, and vital status was conducted in 1993-1994; an additional assessment of treatment and vital status was performed in 1995-1996. RESULTS: Of 188 small tumors not treated at the time of study enrollment, 46 grew during follow-up to a size that was large enough to be eligible for the COMS clinical trials. The Kaplan-Meier estimates of proportion of tumors that grew were 21% (95% confidence interval, 14%-27%) by 2 years and 31% (95% confidence interval, 23%-39%) by 5 years. Factors significantly associated with time to growth in a Cox proportional hazards regression model were greater initial tumor thickness and diameter, presence of orange pigment, absence of drusen, and absence of areas of retinal pigment epithelial changes adjacent to the tumor. CONCLUSIONS: Of small choroidal melanomas initially managed by observation, 21% demonstrated growth by 2 years and 31% by 5 years. The clinical and photographic features of these tumors confirm previous findings and are useful in identifying patients with small tumors at highest risk of short-term growth.

Adult↗
PubMed2001

Transport of nutrients across the choroid plexus.

A brief outline is given first of the early history of the ventricles and the strange ideas of their functions from Galen to the enlightenment of the Renaissance with the work of Versalius. This is followed by a description of the histology of the choroid plexuses (CP) and discussion on the functions of the choroid plexus and on the composition of cerebrospinal fluid (CSF). The methods of measuring the rate of secretion of CSF will be outlined and the possible nutritive functions of the choroid plexuses will be considered. The role of the choroid plexuses in the control of the concentration of glucose and amino acids in CSF will be compared with data from in vitro experiments to that from the isolated vascularly perfused choroid plexuses. The handling of peptides and proteins by the CP and the synthesis of these molecules by this tissue is then discussed and the effects of lead on the synthesis of transthyretin by this tissue. Finally, reference will be made to the extensive neuro-endocrine role of the CP and efflux systems across the tissue for lipid soluble molecules.

Amino Acids↗
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↗
PubMed1977

Radiotherapy of choroidal metastases: breast cancer as primary site.

Forty-two cases of metastatic breast cancer to the choroid treated by radiation therapy were reviewed. Fifteen patients (36%) had bilateral and 27 patients (64%) had unilateral choroidal involvement. In 12 patients (29%) the choroid was the first site of dissemination. The median survival period after choroidal metastases was 10 months. Most patients were treated with Co60 in doses of 2500 rads tumor dose (TD) in ten fractions, 2500 rads, (TD) in five fractions and 3000 rads (TD) in ten fractions. An early group of patients had orthovoltage therapy. Good visual responses were obtained with each of the above treatment programs. Radiation treatment in the range of 2500-3000 rads TD in a short course is recommended for palliation of metastatic breast cancer to the choroid.

Breast Neoplasms↗
PubMed1990

Choroid plexus tumors in the breast cancer-sarcoma syndrome.

Choroid plexus neoplasms are rare epithelial tumors of the central nervous system. A carcinoma of the choroid plexus occurred in a child from a family with the breast cancer-sarcoma syndrome (Li-Fraumeni or SBLA syndrome), an inherited condition characterized by the development of diverse neoplasms (sarcoma, breast cancer, brain tumors, leukemia, adrenal cortical carcinoma, and others). Choroid plexus carcinomas were identified in two kindreds previously reported with the syndrome. The literature contains reports of choroid plexus neoplasms occurring in families and in individuals with multiple primary tumors. Choroid plexus neoplasm may be a manifestation of the inherited proclivity to tumor development in the breast cancer-sarcoma syndrome.

Adolescent↗
PubMed1987

Ultrastructure of the choroid plexus epithelium of pigeons treated with drugs: I. Effect of Thyradin, 2,4-dinitrophenol, and cycloheximide.

Possible changes in the epithelial cells of the pigeon choroid plexus induced by administration of thyroid powder (Thyradin), 2,4-dinitrophenol, and cycloheximide were studied by scanning and transmission electron microscopy. A marked increase in the number of large bulbous and bleblike protrusions on the apical end of the epithelial cells was observed after oral administration of Thyradin for a month. The endoplasmic content of the protrusions consisted mainly of electron-lucent material. These results provide morphological evidence for the stimulatory effect of Thyradin. Intramuscular injections of 2,4-dinitrophenol for 15 days caused the collapse or deformation of the mitochondria and bleblike or bulbous protrusions. This indicates that changes in the surface configuration of the choroid plexus are controlled by an energy-dependent mechanism. The decrease of protrusions and polyribosomes and increase of the tubular saccules of varying electron density, size, and shape were noted in cells after 15 days of intramuscular cycloheximide injection. The electron density of the protrusions is lower than that of the control pigeons. The results of this study suggest that a curious pleomorphic structure on the apical surface of the choroid epithelial cell of pigeon is closely related to the functional state of choroidal cells. The study also demonstrates that a secondary ultrastructural response due to diverse physiologic effects is reflected in the architecture of the choroid plexus cells.

2,4-Dinitrophenol↗
PubMed1981

The lateral, third, and fourth ventricle choroid plexus of the dog: a structural and ultrastructural study.

The morphology of the choroid plexuses of the lateral, third, and fourth ventricles in dogs was studied by histological and ultrastructural techniques after in situ fixation. Most portions of the plexus in the lateral ventricle showed a parallel arrangement of capillaries, producing a fine corrugation of the overlying layer of epithelial cells. Relatively large amounts of connective tissue separated the capillaries from the epithelium. The fourth ventricle choroid plexus showed short capillary loops projecting into the ventricle and more intimately covered by epithelium. Smaller amounts of connective tissue separated the capillaries from the epithelium. The choroid plexus of the third ventricle showed characteristics seen in the plexuses of both the lateral and fourth ventricles. The total surface of the choroid plexuses in the dog averaged 10.7 cm2, of which 55% was fourth ventricle choroid plexus.

Animals↗
PubMed2001

Differentiation of choroid plexus ependymal cells into astrocytes after grafting into the pre-lesioned spinal cord in mice.

Choroid plexus epithelial cells represent a continuation of, and have the same origin as, ventricular ependymal cells, and are regarded as modified ependymal cells. To extend previous studies of the use of choroid plexus ependymal cell (CPEC) grafting for nerve regeneration in the spinal cord, we investigated the capacity of cultured choroid plexus ependymal cells to differentiate into other types of glial cells in the spinal cord tissue. The choroid plexuses were excised from the fourth ventricle of green fluorescent protein (GFP)-transgenic mice and the cells were dissociated and cultured for 4-6 weeks. CPECs were harvested from the monolayer cultures and injected into the pre-lesioned spinal cords of wild-type mice of the same strain using a Hamilton syringe. One week after injection, some GFP-positive transplanted cells became immunohistochemically positive for glial fibrillary acidic protein (GFAP) but negative for neurofilament and myelin basic protein. All the GFAP-positive transplanted cells were negative for vimentin. Two weeks after grafting, immunoelectron microscopy showed that the GFP-positive transplanted cells that had gained GFAP immunoreactivity contained numerous bundles of intermediate filaments, a morphological characteristic similar to that of astrocytes, and were in close contact with adjacent host tissue. These results indicate that, when grafted into the spinal cord, at least some cultured choroid plexus ependymal cells have the capacity to differentiate into astrocytes.

Animals↗
PubMed1990

Distinct positive and negative elements control the limited hepatocyte and choroid plexus expression of transthyretin in transgenic mice.

Transthyretin (TTR) is a thyroid hormone transport protein that is secreted by hepatocytes into the serum and by the choroid plexus epithelium into the cerebral spinal fluid. The protein is not made elsewhere in adult animals in significant amounts. We find that the start site for mRNA synthesis is the same in both cell types. The sequences required for mouse TTR expression in cultured hepatocytes include an enhancer at -1.86 to -1.96 kbp and a promoter-proximal region at -70 to -200 bp relative to the mRNA cap site. We demonstrate that in transgenic mice these regulatory regions (approximately 300 bp) are sufficient for quantitatively normal expression of a TTR minigene in hepatocytes, but not for restricted expression in the choroid plexus cells of the brain. Instead, they direct aberrant widespread expression in regions of the brain outside the choroid plexus. With 3 kbp of upstream sequence the TTR minigene is expressed specifically in the choroid plexus as well as in the liver, demonstrating the normal cell type specificity for TTR. These results suggest that 3 kbp of upstream sequence contains positive element(s) required for choroid plexus expression which are distinct from those utilized in the hepatocyte, and may also contain negative element(s) that function to suppress transcription in other brain cell types.

Animals↗