Intraluminal Carotid Artery Thrombus in COVID-19: Another Danger of Cytokine Storm?

Coronavirus disease 2019 (COVID-19) is associated with a severe inflammatory response. Inflammation affects atherosclerotic plaque vulnerability and promotes a thrombogenic environment. We report a series of 6 patients with COVID-19 with acute ischemic stroke due to intraluminal carotid artery thrombus presenting during an 8-day period. Six patients were included (5 men) with a mean age of 65.8 years (range, 55-78 years). COVID-19 was diagnosed by detection of Severe Acute Respiratory Syndrome coronavirus 2 in 5 patients and was presumed due to typical clinical and imaging findings in 1 patient. All patients had vascular risk factors including diabetes (83%), hyperlipidemia (100%), and smoking (17%). Four patients presented with large infarcts with initial NIHSS scores of 24-30. During their hospitalization, all patients had elevated D-dimer and C-reactive protein levels, 5 patients had elevated lactate dehydrogenase and ferritin levels, 3 had elevated interleukin-6 levels, and 2 had elevated troponin levels. Inflammation related to COVID-19 may result in rupture of vulnerable atherosclerotic plaques, resulting in thrombosis and acute ischemic stroke.

Neuropsychiatric Lupus with Antibody-Mediated Striatal Encephalitis

Systemic lupus erythematosus is a chronic autoimmune disease characterized by the production of autoantibodies resulting in tissue injury across multiple organs; up to 50% of patients develop neurologic involvement, collectively referred to as neuropsychiatric systemic lupus erythematosus. The cases in this clinical report will highlight a subtype of neuropsychiatric systemic lupus erythematosus demonstrating imaging findings of striatal inflammation responsive to plasmapheresis similar to those in the subset of N-methyl-D-aspartate receptor autoimmune encephalitis that involves the striatum. Although the cause for this striking imaging appearance is not definitely known, literature will be presented supporting the hypothesis that it is due to peripheral anti-double-stranded DNA antibodies entering the central nervous system to cross-react with N-methyl-D-aspartate receptor antigens.

CSF Pressure Change in Relation to Opening Pressure and CSF Volume Removed

BACKGROUND AND PURPOSE

Idiopathic intracranial hypertension is a complex neurologic disorder resulting from increased intracranial pressure. Our aim was to determine whether a correlation exists between the CSF pressure-volume relationship, specifically the craniospinal elastance and pressure-volume index, in patients with idiopathic intracranial hypertension and whether opening pressure affects this relationship.

MATERIALS AND METHODS

Lumbar punctures performed for suspected idiopathic intracranial hypertension from 2006 to 2017 were identified. Opening and closing pressures, CSF volume removed, and clinical diagnosis of idiopathic intracranial hypertension were obtained from the medical records. The craniospinal elastance (pressure change per milliliter of CSF removed) and pressure-volume index were calculated, and the Pearson correlation coefficients between both the craniospinal elastance and pressure-volume index and opening pressure were determined. Linear regression models of craniospinal elastance and the pressure-volume index and interaction terms with opening pressure were assessed for covariate influence on this association.

RESULTS

One hundred sixteen patients were included in the final analysis. The mean craniospinal elastance according to opening pressure group was 0.52 ± 0.18 for <20 cm H₂O, 0.57 ± 0.20 for 20-29 cm H₂O, 0.91 ± 0.28 for 30-39 cm H₂O, and 1.20 ± 0.25 for ≥40 cm H₂O. There was a positive linear association between opening pressure and craniospinal elastance with a 0.28 cm H₂O/mL increase in craniospinal elastance (standard error = 0.03, P < .001) for every 10 cm H₂O increase in opening pressure. Of the covariables analyzed, only age older than 50 years and total volume of CSF removed affected this association.

CONCLUSIONS

As opening pressure increases, the craniospinal elastance increases in a linear fashion while the pressure-volume index decreases. Further studies are needed to determine whether these changes relate to the underlying pathophysiology of idiopathic intracranial hypertension or simply represent established CSF volume pressure dynamics.

Autoimmune Encephalitis: Pathophysiology and Imaging Review of an Overlooked Diagnosis

Autoimmune encephalitis is a relatively new category of immune-mediated disease involving the central nervous system that demonstrates a widely variable spectrum of clinical presentations, ranging from the relatively mild or insidious onset of cognitive impairment to more complex forms of encephalopathy with refractory seizure. Due to its diverse clinical features, which can mimic a variety of other pathologic processes, autoimmune encephalitis presents a diagnostic challenge to clinicians. Imaging findings in patients with these disorders can also be quite variable, but recognizing characteristic findings within limbic structures suggestive of autoimmune encephalitis can be a key step in alerting clinicians to the potential diagnosis and ensuring a prompt and appropriate clinical work-up. In this article, we review antibody-mediated encephalitis and its various subtypes with a specific emphasis on the role of neuroimaging in the diagnostic work-up.

Accuracy of 2-Phase Parathyroid CT for the Preoperative Localization of Parathyroid Adenomas in Primary Hyperparathyroidism

BACKGROUND AND PURPOSE

Minimally invasive parathyroidectomy requires accurate preoperative localization of suspected adenomas, and multiphase CT allows adenoma characterization while providing detailed anatomic information. The purpose of this study was to assess the feasibility of a protocol using only arterial and venous phases to localize pathologic glands in patients with primary hyperparathyroidism.

MATERIALS AND METHODS

We identified 278 patients with primary hyperparathyroidism who had undergone 2-phase CT with surgical cure. All scans were read prospectively by board-certified neuroradiologists. A neuroradiology fellow retrospectively reviewed images and reports and classified suspected adenomas on the basis of anatomic location. Accuracy was determined by comparing imaging results with surgical findings. The ability of 2-phase CT to localize adenomas to 1 of 4 neck quadrants and lateralize them to the correct side was assessed. Accuracy of identifying multigland disease was also evaluated.

RESULTS

In patients with single-gland disease, the sensitivity and specificity of 2-phase CT to correctly localize the quadrant were 55.4% and 85.9%, respectively. The sensitivity and specificity of correct lateralization were 78.8% and 67.8%, respectively. The sensitivity and specificity to identify multigland disease were 22.9% and 79.5%, respectively.

CONCLUSIONS

While the 2-phase CT protocol in this study demonstrates lower accuracy compared with reports of other techniques, its lower radiation compared with 3- and 4-phase techniques may make it a feasible alternative for preoperative parathyroid localization. Further prospective studies are needed to identify patients for whom this technique is most suitable.

Primary Cutaneous CD8(+) CD30(+) Anaplastic Large Cell Lymphoma: An Unusual Case with a High Ki-67 index-A Short Review

Primary cutaneous anaplastic large cell lymphoma (PCALCL) is a part of the spectrum of CD30⁺ cutaneous lymphoproliferative disorder, characterized by variable degrees of CD2, CD3, CD4 and CD5 expression by lymphoid cells. PCALCLs with an expression of cytotoxic phenotype (CD8⁺) and cytotoxic proteins are uncommon. Cutaneous CD8⁺ CD30⁺ lymphoproliferative lesions are difficult to classify, diagnose and may be the cause of misdiagnose. CD8⁺ PCALCL must be distinguished from CD8⁺ mycosis fungoides, lymphomatoid papulosis type D and primary cutaneous aggressive epidermotropic CD8⁺ T-cell lymphoma. Usually CD8⁺ PCALCL is an indolent disease with a favorable prognosis, except few cases can show poor outcomes. The high Ki-67 index points toward advanced PCALCL. Treatment modalities include surgical excision, radiotherapy and clinical monitoring. Chemotherapy is reserved for disseminated disease. We report a 59-year-old male presented with rapid development of multiple painful reddish-brown plaques and nodular ulcerative skin lesions over the left thigh region since 2 months. A diagnosis of CD8⁺ PCALCL with a high Ki-67 index was made on the basis of histology and immunohistochemistry, in co-relation with clinical presentation.

In vivo correlation of tumor blood volume and permeability with histologic and molecular angiogenic markers in gliomas

BACKGROUND AND PURPOSE

Tumor angiogenesis is very heterogeneous and in vivo correlation of perfusion imaging parameters with angiogenic markers can help in better understanding the role of perfusion imaging as an imaging biomarker. The purpose of this study was to correlate PCT parameters such as CBV and PS with histologic and molecular angiogenic markers in gliomas.

MATERIALS AND METHODS

Thirty-six image-guided biopsy specimens in 23 patients with treatment-naive gliomas underwent PCT examinations. We correlated MVD, MVCP, VEGFR-2 expression, tumor cellularity, and WHO grade of the image-guided biopsy specimens with the PCT parameters. Histologic sections were stained with hematoxylin-eosin, CD34, and VEGFR-2 and examined under a light microscope. These histologic and molecular angiogenic markers were correlated with perfusion parameters of the region of interest corresponding to the biopsy specimen. Pearson correlation coefficients and multiple regression analyses by using clustering methods were performed to assess these correlations.

RESULTS

CBV showed a significant positive correlation with MVD (r = 0.596, P < .001), whereas PS showed a significant positive correlation with MVCP (r = 0.546, P = .001). Both CBV (r = 0.373, P = .031) and PS (r = 0.452, P = .039) also showed a significant correlation with WHO grade. VEGFR-2 positive specimens showed higher PS and CBV; however, neither was statistically significant at the .05 level.

CONCLUSIONS

CBV showed a significant positive correlation with MVD, whereas PS showed a significant positive correlation with MVCP, suggesting that these 2 perfusion parameters represent different aspects of tumor vessels; hence, in vivo evaluation of these could be important in a better understanding of tumor angiogenesis.

Isolated rupture of the lateral collateral ligament during yoga practice: a case report

We report a case of isolated rupture of the lateral collateral ligament (LCL) of the knee while attempting to place the left foot behind the head during yoga practice. The 34-year-old man had discomfort of the lateral aspect of the knee particularly with varus strain. A magnetic resonance image revealed rupture of the LCL at the insertion onto the fibula. The patient had grade-II laxity of the LCL and was treated non-operatively. At the 12-month follow-up, grade-I laxity of the LCL remained clinically evident, but function was not impaired.

Quantitative estimation of permeability surface-area product in astroglial brain tumors using perfusion CT and correlation with histopathologic grade

BACKGROUND AND PURPOSE

Glioma angiogenesis and its different hemodynamic features, which can be evaluated by using perfusion CT (PCT) imaging of the brain, have been correlated with the grade and the aggressiveness of gliomas. Our hypothesis was that quantitative estimation of permeability surface area product (PS), cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) in astroglial brain tumors by using PCT will correlate with glioma grade. High-grade gliomas will show higher PS and CBV as compared with low-grade gliomas.

MATERIALS AND METHODS

PCT was performed in 32 patients with previously untreated astroglial tumors (24 high-grade gliomas and 8 low-grade gliomas) by using a total acquisition time of 170 seconds. World Health Organization (WHO) glioma grades were compared with PCT parameter absolute values by using Student or nonparametric Wilcoxon 2-sample tests. Receiver operating characteristic (ROC) analyses were also done for each of the parameters.

RESULTS

The differences in PS, CBV, and CBF between the low- and high-grade tumor groups were statistically significant, with the low-grade group showing lower mean values than the high-grade group. ROC analyses showed that both CBV (C-statistic 0.930) and PS (C-statistic 0.927) were very similar to each other in differentiating low- and high-grade gliomas and had higher predictability compared with CBF and MTT. Within the high-grade group, differentiation of WHO grade III and IV gliomas was also possible by using PCT parameters, and PS showed the highest C-statistic value (0.926) for the ROC analyses in this regard.

CONCLUSIONS

Both PS and CBV showed strong association with glioma grading, high-grade gliomas showing higher PS and CBV as compared with low-grade gliomas. Perfusion parameters, especially PS, can also be used to differentiate WHO grade III from grade IV in the high-grade tumor group.

Role of perfusion CT in glioma grading and comparison with conventional MR imaging features

BACKGROUND AND PURPOSE

Perfusion imaging using CT can provide additional information about tumor vascularity and angiogenesis for characterizing gliomas. The purpose of our study was to demonstrate the usefulness of various perfusion CT (PCT) parameters in assessing the grade of treatment-naïve gliomas and also to compare it with conventional MR imaging features.

MATERIALS AND METHODS

PCT was performed in 19 patients with glioma (14 high-grade gliomas and 5 low-grade gliomas). Normalized ratios of the PCT parameters (normalized cerebral blood volume [nCBV], normalized cerebral blood flow [nCBF], normalized mean transit time [nMTT]) were used for final analysis. Conventional MR imaging features of these tumors were assessed separately and compared with PCT parameters. Low- and high-grade gliomas were compared by using the nonparametric Wilcoxon 2-sample tests.

RESULTS

Mean nCBV in the high- and low-grade gliomas was 3.06 +/- 1.35 and 1.44 +/- 0.42, respectively, with a statistically significant difference between the 2 groups (P = .005). Mean nCBF for the high- and low-grade gliomas was 3.03 +/- 2.16 and 1.16 +/- 0.36, respectively, with a statistically significant difference between the 2 groups (P = .045). Cut points of >1.92 for nCBV (85.7% sensitivity and 100% specificity), >1.48 for nCBF (71.4% sensitivity and 100% specificity), and <1.94 for nMTT (92.9% sensitivity and 40% specificity) were found to identify the high-grade gliomas. nCBV was the single best parameter; however, using either nCBV of >1.92 or nCBF of >1.48 improved the sensitivity and specificity to 92.9% and 100%, respectively. The sensitivity and specificity for diagnosing a high-grade glioma with conventional MR imaging were 85.7% and 60%, respectively.

CONCLUSIONS

PCT can be used for preoperative grading of gliomas and can provide valuable complementary information about tumor hemodynamics, not available with conventional imaging techniques. nCBV was the single best parameter correlating with glioma grades, though using nCBF when nCBV was <1.92 improved the sensitivity. An nCBV threshold of >1.92 was found to identify the high-grade gliomas.

MRI-guided, open trial of abciximab for ischemic stroke within a 3- to 24-hour window

The authors assessed the effect of IV abciximab on early neurologic improvement and ischemic lesion growth in 29 patients with supratentorial stroke and NIH stroke scale score (NIHSSS) > or = 4 (11.1 +/- 5.9), treated within 3 to 24 (13.6 +/- 5.5) hours of onset. The 48 to 72-hour NIHSSS improvement was 4.4 +/- 3.2 and the 24-hour lesion growth on DWI was +23% (-50%, +103%); 7/26 (27%) patients experienced lesion size decrease. Treatment of sub-24-hour stroke with abciximab improves early post-treatment neurologic status and often attenuates ischemic lesion growth.

Neuronal localization and association of Niemann Pick C2 protein (HE1/NPC2) with the postsynaptic density

Niemann-Pick disease type C (NP-C) is an inherited disorder that is characterized biochemically by cellular cholesterol and glycolipid storage, and clinically by progressive neurodegeneration. Most cases of NP-C are caused by inactivating mutations of the npc1 gene, but about 5% are linked to npc2, which encodes a soluble cholesterol binding protein, previously identified as epididymal secretory glycoprotein 1 (HE1). The present study was carried out to investigate the immunocytochemical localization of HE1/NPC2 protein in the mouse brain. Using an antibody against recombinant HE1/NPC2, we found HE1/NPC2 to be localized predominantly in neurons in the brain. Immunoreactivity for HE1/NPC2 was observed in pyramidal or projection neurons in the cerebral cortex and amygdala, and Purkinje neurons in the cerebellum. Neurons in the thalamus, hypothalamus, and globus pallidus were lightly labeled, or unlabeled. This regional pattern of expression of HE1/NPC2 is similar to our previous findings with NPC1, with a low level of expression of both NPC1 and HE1/NPC2 proteins in regions derived from the diencephalon, such as the thalamus and hypothalamus. In contrast to NPC1, however, which is predominantly in astrocytes, HE1/NPC2 was observed mainly in neurons. Electron microscopic immunocytochemistry showed that HE1/NPC2 is present in the cytosol of dendrites and on post-synaptic densities (PSD). The occurrence of HE1/NPC2 in the PSD was confirmed by Western blots of PSD-enriched brain subcellular fractions that showed the presence of HE1/NPC2 together with the PSD-associated protein, PSD-95. These results suggest that NPC1 and HE1/NPC2 are differentially enriched in astrocytes and neurons, respectively, and that HE1/NPC2 may function in supporting the integrity of the PSD of neurons.

Laparoscopic appendicectomy at the Aga Khan Hospital, Nairobi

OBJECTIVE

To evaluate our experience of laparoscopic appendicectomy at the Aga Khan Hospital, Nairobi over a six year period from the inception of the technique and to assess its advantages and disadvantages.

DESIGN

Case series study.

SETTING

The Aga Khan Hospital, Nairobi.

PATIENTS

One hundred and six cases operated on from May 1996 to June 2002.

MAIN OUTCOME MEASURES

Clinical presentation, age and sex demographics, average hospital stay, operating time, intra-operative and post-operative complications and outcome.

RESULTS

There was a female preponderance with a female to male ratio of 2:3:1. Mean age was 30.6 years. There was a slightly more number of patients with recurrent appendicitis as opposed to the acute form. Totally laparoscopic procedure was in 39.6% of the cases, laparoscopic assisted in 45.3%. The conversion rate to an open procedure was 15.1%. Post operative port-site infection was 8.5%. No mortality was reported in these series. However there was one case which required re-operation following significant port site haemorrhage. Mean post-operative hospital stay was 2.2 days.

CONCLUSION

Laparoscopic appendicectomy is a safe procedure in well trained hands. The major advantages are less morbidity and excellent cosmesis. Discovery of other intraabdominal pathologies is possible through laparoscopy as opposed to classical appendicectomy.

Differential trafficking of the Niemann-Pick C1 and 2 proteins highlights distinct roles in late endocytic lipid trafficking

The cellular location of Niemann-Pick C2 protein (NPC2) in cultured human fibroblasts and Chinese hamster ovary cells was examined immunocytochemically and in living cells by expression of a functional red fluorescent protein chimeric analogue.

RESULTS

NPC2 is present in the lysosomes of both cholesterol-depleted and -replenished cells, unlike Niemann-Pick C1 protein (NPC1) which is recruited to late endosomes only upon uptake of low-density lipoprotein. With mobilization of cholesterol from lysosomes, immunocytochemical detection of NPC2 in lysosomes is greatly diminished, whereas NPC1 remains in the late endosomal compartment. We found a partial overlap in the trafficking and organellar sites of accumulation of NPC2 and NPC1. In living cells, NPC2 traffics with NPC1 in late endosomal tubules. However, in contrast to NPC1, which remains either in late endosomal vesicles and tubules or at the peripheries of cholesterol-laden lysosomes, NPC2 moves into the central core of lysosomes. Glycolipid analysis reveals that, in contrast to null mutant NPC1 cells, which accumulate GM2 ganglioside only at the plasma membrane, with no endocytic storage, absence of NPC2 protein in null mutant NPC2 cells does not block internalization of GM2 into endocytic vesicles. This difference in the cellular distribution of GM2 in NPC1 and NPC2 null mutants is the first report of a variation in the phenotypic expression of these genotypically distinct lesions.

CONCLUSION

We speculate that while NPC1 may play a major role in the sorting of glycolipids as well as cholesterol within the late endosomes, NPC2 primarily plays a role in the egress of cholesterol and, potentially, glycolipids from lysosomes. These proteins appear not to be integrated into a tightly bound biological complex, but rather represent separate functional entities that complement each other.

Functional MRI-BOLD of brainstem structures during visually triggered migraine

BACKGROUND

Previously, hyperoxia and blood volume increase were reported in the red nucleus and substantia nigra during spontaneous migraine with aura.

OBJECTIVE

To further understand the pathophysiologic role of these centers, activation of brainstem structures was investigated in patients with visually triggered migraine.

METHODS

Twenty-six patients with migraine (23 with aura and 3 without aura), and 10 normal control subjects were studied with blood oxygen level-dependent (BOLD) fMRI during repeated checkerboard visual stimulation. Three axial image sections, which covered the occipital cortex and brainstem, were acquired 224 times with a temporal resolution of 3.5 seconds.

RESULTS

Repetitive visual stimulation triggered symptoms in 12 patients; four who had migraine with aura developed both visual symptoms and headaches, and six who had migraine with aura and two who had migraine without aura had headaches only. Four patients who had migraine with aura experienced the onset of their usual aura or onset of their typical headache either during the experiment or immediately after. In the remaining 10 patients with migraine, and all control subjects, visual stimulation failed to trigger symptoms at any time. In 75% of the patients who developed symptoms during stimulation, baseline T2*-weighted MR signal intensities increased in the red nucleus and substantia nigra before occipital cortex signal elevation or the onset of visually triggered symptoms.

CONCLUSION

Activation (hyperoxia and blood volume increase) of the red nucleus and substantia nigra in association with visually triggered symptoms of migraine suggest that these brainstem structures are a part of a neuronal network activated during an attack.

Lack of clinical significance of early ischemic changes on computed tomography in acute stroke

CONTEXT

The prevalence and clinical significance of early ischemic changes (EICs) on baseline computed tomography (CT) scan of the head obtained within 3 hours of ischemic stroke are not established.

OBJECTIVE

To determine the frequency and significance of EIC on baseline head CT scans in the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA (recombinant tissue plasminogen activator) Stroke Trial.

DESIGN AND SETTING

The original study, a randomized controlled trial, took place from January 1991 through October 1994 at 43 sites, during which CT images were obtained within 3 hours of symptom onset and prior to the initiation of rt-PA or placebo. For the current analysis, detailed reevaluation was undertaken after October 1994 of all baseline head CT scans with clinical data available pretreatment (blinded to treatment arm).

PATIENTS

Of 624 patients enrolled in the trial, baseline CT scans were retrieved and reviewed for 616 (99%).

MAIN OUTCOME MEASURES

Frequency of EICs on baseline CT scans; association of EIC with other baseline variables; effect of EICs on deterioration at 24 hours (>/=4 points increase from the baseline National Institutes of Health Stroke Scale [NIHSS] score); clinical outcome (measured by 4 clinical scales) at 3 months, CT lesion volume at 3 months, death at 90 days; and symptomatic intracranial hemorrhage (ICH) within 36 hours of treatment.

RESULTS

The prevalence of EIC on baseline CT in the combined rt-PA and placebo groups was 31% (n = 194). The EIC was significantly associated with baseline NIHSS score (rho = 0.23; P<.001) and time from stroke onset to baseline CT scan (rho = 0.11; P =.007). After adjusting for baseline variables, there was no EIC x treatment interaction detected for any clinical outcome, including deterioration at 24 hours, 4 clinical scales, lesion volume, and death at 90 days (P>/=.25), implying that EIC is unlikely to affect response to rt-PA treatment. After adjusting for NIHSS score (an independent predictor of ICH), no EIC association with symptomatic ICH at 36 hours was detected in the group treated with rt-PA (P>/=.22).

CONCLUSIONS

Our analysis suggests that EICs are prevalent within 3 hours of stroke onset and correlate with stroke severity. However, EICs are not independently associated with increased risk of adverse outcome after rt-PA treatment. Patients treated with rt-PA did better whether or not they had EICs, suggesting that EICs on CT scan are not critical to the decision to treat otherwise eligible patients with rt-PA within 3 hours of stroke onset.

Neurodegeneration in Niemann-Pick type C disease mice

Niemann-Pick disease type C (NP-C) is an inherited neurodegenerative disorder associated with intracellular cholesterol and glycolipid trafficking defects. Two separate genes, NPC1 and NPC2, have been linked to NP-C. NPC1 encodes a polytopic membrane-bound protein with a putative sterol-sensing domain. NPC2 has been recently identified as epididymal secretory glycoprotein 1. The NPC1 protein functions in the vesicular redistribution of endocytosed lysosomal cargo, but how its inactivation leads to neurodegeneration is not known. The neurological symptoms of NP-C typically appear after a period of normal early development and reflect progressive degeneration of widespread brain regions. Here we have delineated the pattern of neurodegeneration in NP-C mice, whose genetic defect has been shown to be an inactivating mutation of the mouse NPC1 gene. The results reveal a spatially and temporally specific pattern of degeneration of nerve fibers followed by degeneration of neuronal cell bodies beginning as early as day 9 and continuing throughout life. We have recently showed that in the primate brain, the NPC1 protein is localized predominantly within perisynaptic astrocytic processes. The present observations suggest that a functional disturbance in NPC1 could disrupt vesicular transport of cholesterol, glycolipids and possibly other endocytic cargo in glia, which is critical for maintaining the integrity of neurons.

Cytokine modulation of costimulatory molecules on human fetal retinal pigment epithelial cells

PURPOSE

Experiments were performed to evaluate the effect of various pro- and anti-inflammatory cytokines on the human fetal retinal pigment epithelium's (HFRPE) expression of major histocompatibility complex (MHC) and costimulatory molecules.

METHODS

Pure cultures of HFRPE cells were isolated. HFRPE cells were incubated in the presence of Interferon-gamma (IFN-gamma), IFN-beta, Tumor Necrosis Factor-alpha (TNF-alpha), Interleukin-1beta (IL-1beta), Tumor Growth Factor-beta (TGF-beta), and a combination of IFN-gamma and TGF-beta (pre-incubation and simultaneously incubated). The expression of MHC class I and class II, Intercellular cell adhesion molecule (ICAM-1), B7-1 (CD80), and B7-2 (CD86) molecules was quantitatively analyzed by flow cytometry.

RESULTS

The cultured HFRPE cells expressed high levels of MHC class I and low levels of MHC class II and ICAM-1 molecules. After culture with the above mentioned cytokines, IFN-gamma up-regulated the HFRPE's expression of MHC class II and ICAM-1. IFN-beta and IL-beta1 only up-regulated the expression of ICAM-1. TGF-beta was unable to suppress the up-regulatory effect of IFN-gamma in HFRPE cells (pre-incubated and simultaneously incubated). The other cytokines did not have any significant effect on HFRPE's expression of MHC I and II or the selected costimulatory molecules.

CONCLUSIONS

Our findings indicate that TGF-beta cannot suppress up-regulating effects of IFNgamma- on HFRPE's expression of MHC and costimulatory molecules. Overall, the weak or lack of expression of costimulatory molecules after stimulation with various cytokines further confirms that HFRPE cells are weak antigen presenting cells.

Necrotizing fasciitis of abdominal wall in AIDS

Necrotizing fasciitis (NF) is an uncommon but potentially lethal soft-tissue infection. Mortality rate is high and has not changed since it was first described by Meleny. Although immunodeficiency is a risk factor for NF, there is only one reported case of NF in AIDS involving the cervical region. We report the first case of necrotizing fasciitis of the abdominal wall in an AIDS patient.

Immunocytochemical localization of apolipoprotein D in oligodendrocyte precursor-like cells, perivascular cells, and pericytes in the human cerebral cortex

Apolipoprotein D, a lipocalin transporter of small hydrophobic molecules including sterols, steroid hormones and arachidonic acid, is a widely expressed protein in peripheral and neural tissues. It has been shown to be upregulated in the context of neural injury, and with neuronal degeneration and regeneration. Here we have used light and electron microscopic immunocytochemistry with immunogold labeling to delineate the pattern of expression of apoD in the human brain. Our results confirm previous observations that apoD is a predominantly glial protein in the nervous system. In addition we have found that apoD is present in the cytosol and outer membrane of the nuclear envelope of glial cells in the neuropil. The labeled glial cells were putatively identified as a population of oligodendrocyte precursor cells. Immunoreactivity was also associated with the cytosol of perivascular cells, and lysosomes of pericytes, in the walls of blood vessels. These observations suggest a potential role for glial cells and apoD, in the transport of sterols and small hydrophobic molecules to, or from, blood vessels in the cortex.

Macular hole surgery in high myopia

PURPOSE

To evaluate the anatomic and functional outcomes of macular hole surgery in high myopia and to determine whether surgery is beneficial in myopic eyes with macular holes.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

Twenty eyes of 18 highly myopic subjects who underwent pars plana vitrectomy for macular holes.

METHODS

We analyzed demographics, preoperative, and postoperative characteristics in 20 eyes with macular holes with a mean of 10.4 months duration and myopia of 6 diopters or greater.

MAIN OUTCOME MEASURES

Macular hole closure rate and mean visual acuity preoperatively and postoperatively.

RESULTS

Mean subject age was 56.4 years and preoperative visual acuity was 20/100+2. The macular hole was closed with one surgery in 60.0% of eyes and in 85.0% of eyes with one or more surgeries. The mean final acuity in all eyes was 20/63, and 40.0% improved greater than three Snellen lines at the final visit. The use of adjunctive agents seemed to have no effect on macular hole closure or visual acuity. A subgroup of three myopic eyes with retinal detachments surrounding the macular hole had successful closure with visual acuity improvement in two of three eyes.

CONCLUSIONS

Macular hole surgery can give substantial visual improvement in myopic eyes with macular holes, but the anatomic closure rates are lower than in eyes with idiopathic macular holes, and thus a higher reoperation rate is required.

Human fetal retinal pigment epithelium-induced cell cycle arrest, loss of mitochondrial membrane potential and apoptosis

PURPOSE

To investigate the mechanism of action of the soluble immune suppressive product secreted by human fetal retinal pigment epithelial (HFRPE) cells in a model system using the human T-cell line Jurkat (Jkt).

METHODS

Pure HFRPE cells were isolated and cultured. The supernatants of both nonactivated and IFN-gamma-activated HFRPE cells were isolated. Cells from the human T-cell line Jkt were incubated either in standard culture medium or in the supernatant isolated from HFRPE cells. In the first assay Jkt cell proliferation was measured by [(3)H]thymidine incorporation. In the second assay Jkt cell apoptosis was examined for annexin V staining by flow cytometry. In the third assay Jkt cell division was evaluated with carboxyfluorescein succinimidyl ester (CFSE) fluorescent dye. In the last assay the mitochondrial transmembrane potential of Jkt cells was measured with the cationic lipophilic fluorochrome 3,3'-dihexyloxacarbocyanine iodide [DiOC(6)]. In all the assays the effect of supernatants isolated from both nonactivated and IFN-gamma-activated HFRPE cells were compared with standard culture medium. The involvement of antiapoptotic human gene bcl-x(L:)was determined by using a Jkt cell line that was stably transfected with bcl-x(L:).

RESULTS

The supernatant isolated from HFRPE cells significantly suppressed the cell division in Jkt cells and induced apoptosis. These effects were stronger when the supernatant was isolated from IFN-gamma-activated HFRPE cells. The apoptosis pathway induced by the secreted product of HFRPE cells involved the early disruption of mitochondrial transmembrane potential. Although the overexpression of bcl-x(L) gene rescued the Jkt cells from supernatant-induced apoptosis, it could not restore the proliferation of Jkt cells.

CONCLUSIONS

These data suggest that HFRPE cells secrete a product that initiates an early cell cycle arrest in the human T-cell line Jkt, which is followed by the activation of an apoptotic pathway that involves the loss of mitochondrial membrane potential. The latter could be prevented by bcl-x(L) overexpression. Also these data suggest that the HFRPE-induced T-cell apoptosis may play a significant role in maintaining the immune privilege in the subretinal space.

Regional distribution of NPC1 protein in monkey brain

NPC1 is a member of a family of polytopic membrane-bound proteins with sterol-sensing domains. Inactivating mutations of NPC1 are responsible for most cases of Niemann-Pick type C disease, whose hallmark is progressive neurodegeneration. The precise molecular mechanisms whereby defective NPC1 function leads to neurodegeneration are unknown. In the brain, we have previously found NPC1 to localize predominantly within perisynaptic astrocytic processes. Here we have mapped the regional distribution of NPC1 in the monkey brain. Dense NPC1 immunoreactivity was observed in telencephalic structures, including the cerebral neocortex, hippocampus, caudate nucleus and putamen, whilst light immunostaining was observed in diencephalic structures, including the globus pallidus, thalamus and hypothalamus. Light staining was also generally observed in the midbrain, pons, medulla oblongata and cerebellum, except the inferior olive, which was densely stained. By light microscopy, only a few indistinctly labeled cell bodies were observed even within densely labeled regions, where most of the immunoreactivity appeared to be due to the large numbers of labeled cellular processes. On electron microscopy, these processes were identified as glial, and not neuronal. The astrocytic localization of NPC1 was further confirmed by double labeling for NPC1 and GFAP. The regional pattern of NPC1 expression suggests that areas normally expressing low levels of the NPC1 protein are more susceptible to neuronal degeneration in Niemann-Pick type C disease.

Insulin-like growth factor 1 regulates developing brain glucose metabolism

The brain has enormous anabolic needs during early postnatal development. This study presents multiple lines of evidence showing that endogenous brain insulin-like growth factor 1 (Igf1) serves an essential, insulin-like role in promoting neuronal glucose utilization and growth during this period. Brain 2-deoxy-d- [1-(14)C]glucose uptake parallels Igf1 expression in wild-type mice and is profoundly reduced in Igf1-/- mice, particularly in those structures where Igf1 is normally most highly expressed. 2-Deoxy-d- [1-(14)C]glucose is significantly reduced in synaptosomes prepared from Igf1-/- brains, and the deficit is corrected by inclusion of Igf1 in the incubation medium. The serine/threonine kinase Akt/PKB is a major target of insulin-signaling in the regulation of glucose transport via the facilitative glucose transporter (GLUT4) and glycogen synthesis in peripheral tissues. Phosphorylation of Akt and GLUT4 expression are reduced in Igf1-/- neurons. Phosphorylation of glycogen synthase kinase 3beta and glycogen accumulation also are reduced in Igf1-/- neurons. These data support the hypothesis that endogenous brain Igf1 serves an anabolic, insulin-like role in developing brain metabolism.

Neuronal localization of sterol regulatory element binding protein-1 in the rodent and primate brain: a light and electron microscopic immunocytochemical study

Sterol regulatory element binding proteins are membrane-bound transcription factors that activate expression of several genes controlling cellular cholesterol and fatty acid homeostasis. The present study aimed to investigate the in vivo expression of sterol regulatory element binding protein-1 in the normal rodent and primate brain, and in the brain in Niemann-Pick type C disease mice. These mutant animals have lysosomal cholesterol accumulation and progressive neurodegeneration caused by an inactivating mutation of the NPC1 gene whose protein product functions in vesicular lipid trafficking. Western blot analysis of rat hippocampal homogenates with an affinity purified rabbit polyclonal antibody directed against an internal epitope of sterol regulatory element binding protein-1 identified a major 68,000 mol. wt protein consistent with the amino-terminal, transcriptionally active fragment of sterol regulatory element binding proteins-1. Immunocytochemically, this antibody revealed dense sterol regulatory element binding protein-1 staining of nuclei and light staining of the cytoplasm of cells in the neocortex and hippocampus in the rat, mouse and monkey brain. By electron microscopy of immunogold-labeled brain sections, these densely labeled cells were found to be neurons. In contrast, normal glial cells had little or no sterol regulatory element binding protein-1 immunoreactivity even at a developmental stage (postnatal day 9) which coincides with active myelination in the rat brain. Also, in contrast to the normal mouse brain, Niemann-Pick type C mice showed reduced staining of cortical and hippocampal neuronal nuclei. Since sterol regulatory element binding protein-1 has been shown to be a transcriptional regulator of fatty acid synthesis in vivo, the current findings of a predominantly neuronal nuclear expression of the 68,000 mol. wt transcriptionally active fragment of sterol regulatory element binding protein-1 highlights the established role of phospholipid metabolites and other fatty-acid containing lipids in neuronal signal transduction and other neuronal functions. Reduced sterol regulatory element binding protein-1 expression in neurons in Niemann-Pick type C may reflect a deficiency in fatty acid synthesis that could contribute to the neuronal dysfunction in this disorder.

Receptors for dopamine and somatostatin: formation of hetero-oligomers with enhanced functional activity

Somatostatin and dopamine are two major neurotransmitter systems that share a number of structural and functional characteristics. Somatostatin receptors and dopamine receptors are colocalized in neuronal subgroups, and somatostatin is involved in modulating dopamine-mediated control of motor activity. However, the molecular basis for such interaction between the two systems is unclear. Here, we show that dopamine receptor D2R and somatostatin receptor SSTR5 interact physically through hetero-oligomerization to create a novel receptor with enhanced functional activity. Our results provide evidence that receptors from different G protein (heterotrimeric guanine nucleotide binding protein)-coupled receptor families interact through oligomerization. Such direct intramembrane association defines a new level of molecular crosstalk between related G protein-coupled receptor subfamilies.

A model for xenogenic immune response

PURPOSE

To develop a model for analyzing the immune response after xenogenic human fetal retinal pigment epithelium (HFRPE) transplantation.

MATERIALS AND METHODS

Pure sheets of HFRPE cells were isolated and attached to poly (DL-lactide-co-glycolide) polymer films and HFRPE spheroids were formed. The spheroids were transplanted into the subretinal space of New Zealand albino rabbits and were observed for 5 months. Bare polymer films were transplanted into the subretinal space of Dutch Belted pigmented rabbits, serving as control.

RESULTS

The polymer film was biodegraded within 3 weeks in the subretinal space. No signs of inflammation in the retina or choroid were observed. The HFRPE spheroids were easily transplanted into the subretinal space. The immune response was followed with ophthalmoscopy. Light microscopy indicated a localized immune response in the transplanted area in which the retina and the choroid were infiltrated with immune cells. This infiltration was denser in the choroid.

CONCLUSIONS

HFRPE spheroid transplantation may be utilized as a model for studying the xenogenic immune response after HFRPE transplantation. This model may also have applications in evaluating the role of immune suppressive agents in preventing rejection after HFRPE transplantation.

Laparoscopic cholecystectomy at the Aga Khan Hospital, Nairobi

OBJECTIVE

To evaluate our experience of laparoscopic cholecystectomies at the Aga Khan Hospital, Nairobi over a three-year period from the inception of the technique, and to assess its value and advantages to the patients.

DESIGN

A prospective case series study.

SETTING

The Aga Khan Hospital, Nairobi.

PATIENTS

One hundred and thirty five cases operated from February 1996 to April 1999. All patients were subjected to the American method of laparoscopic cholecystectomy, which is described in detail in this paper.

MAIN OUTCOME MEASURES

Clinical presentation, age and sex demographics, average hospital stay, intraoperative and postoperative complications and outcome.

RESULTS

There was a female preponderance with a female to male ratio of 5:1. Mean age was forty nine years. Majority of patients suffered from chronic cholecystitis. The conversion rate to an open procedure was five per cent. There were two cases of significant bile leakage which required laparotomy. No mortality was reported in this series.

CONCLUSION

This technique was found to have distinct advantages such as shorter hospital stay, lesser postoperative pain and very good cosmesis. It is a safe procedure if performed by a well trained surgeon.

Algorithm for interpreting the results of frequency doubling perimetry

PURPOSE

To evaluate an algorithm for the identification of glaucomatous visual field defects with the screening mode of frequency doubling technology.

METHODS

Screening-mode frequency doubling technology and Swedish interactive threshold algorithm perimetry were performed on 137 of 150 consecutive patients referred to a glaucoma specialist. We created an algorithm for the frequency doubling technology that gave increased importance to both more severe defects and defects closer to fixation. These values were then compared with the results of the Swedish interactive threshold algorithm visual fields evaluated by the glaucoma hemifield test, two masked glaucoma specialists, and a published definition of glaucomatous damage to determine sensitivity and specificity of the frequency doubling technology screening mode for detecting glaucoma.

A meta-analysis of the Papanicolaou smear and wet mount for the diagnosis of vaginal trichomoniasis

PURPOSE

To obtain reliable estimates of the sensitivity and specificity of the cervical Papanicolaou (Pap) smear and wet mount to diagnose vaginal trichomoniasis.

METHODS

Articles indexed in MEDLINE (1976-1998) about diagnostic tests for trichomoniasis and their listed references were retrieved. Thirty studies (9,501 patients) that used trichomonas culture as a gold standard were selected. Studies were defined as level I if they fulfilled at least two of the following three criteria: consecutive patients were evaluated prospectively, the decision to culture was not influenced by test results, and there was independent and blind comparison with culture. Studies were classified as level II if one criterion was fulfilled, and as level III otherwise.

RESULTS

The pooled sensitivity of the Pap smear for the diagnosis of trichomoniasis among level I studies was 57% (95% confidence interval [CI]: 51% to 63%) and the pooled specificity was 97% (95% CI: 93% to 100%). The likelihood ratio for a positive Pap smear was 19 among level I studies (range: 8 to 62). The pooled sensitivity of the wet mount among level I studies was 58% (95% CI: 51% to 66%); among level II studies, the sensitivity was 72% (95% CI: 62% to 81%), and among level III studies, the sensitivity was 82% (95% CI: 67% to 97%). The overall specificity of the wet mount was 99.8%.

CONCLUSIONS

A positive Pap smear for trichomonads in settings in which trichomoniasis is common (prevalence > or =20%) requires treatment. A positive Pap smear is indeterminate when the prevalence of trichomoniasis is about 10%; thus, clinicians should either confirm the diagnosis by culture or treat all such patients, recognizing that some patients will be treated unnecessarily. A culture should be obtained in women with a positive Pap smear who are unlikely to have trichomoniasis (prevalence < or =1%). While a positive wet mount is diagnostic, a negative wet mount does not exclude trichomoniasis.

Reporting and concordance of methodologic criteria between abstracts and articles in diagnostic test studies

OBJECTIVE

To evaluate the quality and concordance of methodologic criteria in abstracts versus articles regarding the diagnosis of trichomoniasis.

STUDY DESIGN

Survey of published literature.

DATA SOURCES

Studies indexed in MEDLINE (1976-1998).

STUDY SELECTION

Studies that used culture as the gold or reference standard.

DATA EXTRACTION

Data from abstract and articles were independently abstracted using 4 methodologic criteria: (1) prospective evaluation of consecutive patients; (2) test results did not influence the decision to do gold standard; (3) independent and blind comparison with gold standard; and (4) broad spectrum of patients used. The total number of criteria met for each report was calculated to create a quality score (0-4).

MEASUREMENTS AND MAIN RESULTS

None of the 33 abstracts or full articles reported all 4 criteria. Three criteria were reported in none of the abstracts and in 18% of articles (95% confidence interval [95% CI] 8.6% to 34%). Two criteria were reported in 18% of abstracts (95% CI, 8.6% to 34%) and 42% of articles (95% CI, 27% to 59%). One criterion was reported in 42% of abstracts (95% CI, 27% to 59%) and 27% of articles (95% CI, 15% to 44%). No criteria were reported in 13 (39%) of 33 abstracts (95% CI, 25% to 56%) and 4 (12%) of 33 articles (95% CI, 4.8% to 27%). The agreement of the criteria between the abstract and the article was poor (kappa -0.09; 95% CI, -0.18 to 0) to moderate (kappa 0.53; 95% CI, 0.22 to 0.83).

CONCLUSIONS

Information on methods basic to study validity is often absent from both abstract and paper. The concordance of such criteria between the abstract and article needs to improve.

The persistent stapedial artery

The persistent stapedial artery is a rare congenital vascular anomaly that may present as a pulsatile middle ear mass or that may appear as an incidental finding. Five cases of persistent stapedial artery are presented. The CT findings include the absence of the ipsilateral foramen spinosum and a soft-tissue prominence in the region of the tympanic segment of the facial nerve. Three cases were associated with an aberrant internal carotid artery. Imaging identification of this variant may obviate unnecessary surgery and may help in planning surgical or endovascular interventions.

Systematic review of diagnostic tests for vaginal trichomoniasis

OBJECTIVE

To review critically and to summarize the evidence of diagnostic tests and culture media for the diagnosis of Trichomonas vaginitis.

METHODS

We performed a systematic review of literature indexed in MEDLINE of studies that used Trichomonas culture as the reference standard (9,882 patients, 35 studies). Level I studies (5,047 patients, 13 studies) fulfilled at least two of three criteria: 1) consecutive patients were evaluated prospectively, 2) decision to culture was not influenced by test results, and 3) there was independent and blind comparison to culture.

RESULTS

The sensitivity of the polymerase chain reaction technique (PCR) was 95% (95% CI 91% to 99%), and the specificity was 98% (95% CI 96% to 100%). One study was classified as Level I evidence (52 patients). The sensitivity of the enzyme-linked immunosorbent assay was 82% (95% CI 74% to 90%), and the specificity was 73% (95% CI 35% to 100%). The sensitivity of the direct fluorescence antibody was 85% (95% CI 79% to 90%), and the specificity was 99% (95% CI 98% to 100%). Sensitivities of culture media were 95% for Diamond's, 96% for Hollander, and 95% for CPLM.

CONCLUSIONS

The sensitivity and specificity of tests to diagnose trichomoniasis vary widely.

Sarcomas of the head and neck

Sarcomas are rare malignancies of mesenchymal origin. Computed tomographic and magnetic resonance imaging characteristics, as well as histologic findings and epidemiology, of sarcomas of the head and neck are reviewed. The sarcomas discussed include rhabdomyosarcoma, fibrosarcoma, osteosarcoma, chondrosarcoma, malignant fibrous histiocytoma, leiomyosarcoma, alveolar soft part sarcoma, Ewing's sarcoma, and synovial sarcoma. The imaging findings of these entities frequently are nonspecific. Imaging, particularly magnetic resonance imaging, has a major role in defining the extent of these tumors. This is important because complete surgical excision is the preferred method of treatment. Imaging also is useful in planning radiation therapy and determining prognosis.

Cerebral hemorrhagic complications of thrombolytic therapy

Thrombolytic therapy is well established in the management of a select group of atherothrombotic and thromboembolic diseases at the expense of definite but increased risk of intracranial hemorrhage. The incidence of intracranial hemorrhage is higher (6.4% to 20%) in the thrombolytic treatment of acute ischemic stroke, whereas the cerebral hemorrhagic complications of thrombolytic treatment in acute myocardial infarction, acute pulmonary embolism, deep venous thrombosis, and arterial and graft occlusion is less than 2%. Although systemic fibrinolysis after thrombolysis is responsible for hemorrhagic complications, many factors are implicated in predisposition to cerebral hemorrhagic complications such as old age, untreated or chronic hypertension, history of cardiac disease, hyperglycemia, patients with small body mass, previous stroke, longer therapeutic treatment window, increasing neurological deficit or severity of neurological deficit, higher thrombolytic dose and computed tomography findings of mass effect, edema, or extended infarct sign involving more than one third of the territory of the middle cerebral artery. Although the knowledge of different factors associated with intracranial hemorrhage is important, it is the judicious use and strict adherence of appropriate clinical protocols in different clinical settings of thrombolytic treatment and avoidance of the contra-indications that will minimize the rate of hemorrhagic complication to achieve good clinical outcome and desired benefit.

Human fetal retinal pigment epithelium suppresses the activation of CD4(+) and CD8(+) T-cells

BACKGROUND

The suppressive effect of human fetal retinal pigment epithelium (HFRPE) on the activation of human CD4(+) and CD8(+) T-cells was evaluated in vitro.

METHODS

Pure populations of CD4(+) and CD8(+) T-cells were isolated from human peripheral blood-derived buffy coats by negative immunomagnetic selection. The purity of the cells was examined by flow cytometry using anti-CD3-FITC, anti-CD4-FITC, anti-CD8-PE, and anti-CD20-PE mAbs. HFRPE cells were isolated from fetal eyes and pure cultures were obtained. The effect of normal or IFN-gamma-activated HFRPE cells at early (P3) or late (P6) passages on the activation of CD4(+) and CD8(+) T-cells was assessed in two different T-cell activation assays. In both activation models anti-CD3 mAb (OKT3) provided the antigen-specific signal. The secondary signal for the activation of CD4(+) and CD8(+) T-cells was provided with anti-CD18 mAb (TS1/18) and anti-CD28 mAb (9.3) in the first and the second assay respectively. Cross-linking of these soluble mAbs was performed with sheep-anti-mouse IgG-coated latex beads. The T-cell activation was determined by cell proliferation measured by [(3)H]thymidine incorporation. In each activation assay T-cells were incubated with HFRPE cells in a ratio of T-cells to HFRPE of 1:1 or 1:4.

RESULTS

CD4(+) and CD8(+) T-cells were activated by cross-linking CD3 and CD18 in the first assay (CD3/CD18) and CD3 and CD28 in the second assay (CD3/CD28). In both assays HFRPE inhibited the activation of CD4(+) and CD8(+) T-cells. IFN-gamma-activated HFRPE cells totally suppressed the T-cell activation at a 1:1 ratio. This suppressive effect was weaker at lower cell ratios. Some donor variation was observed in the inhibition at the lower cell ratios, especially for the inhibition of CD8(+) T-cell activation with anti-CD3/CD18. The passaging of HFRPE cells did not alter their suppressive effect on CD4(+) and CD8(+) T-cells.

CONCLUSIONS

HFRPE cells suppressed the activation of both CD4(+) and CD8(+) T-cells in vitro. These findings suggest that RPE-induced immune suppression may play a significant role in maintaining immune privilege in the subretinal space.

Increased expression of apolipoprotein D following experimental traumatic brain injury

Increasing evidence suggests that apolipoprotein D (apoD) could play a major role in mediating neuronal degeneration and regeneration in the CNS and the PNS. To investigate further the temporal pattern of apoD expression after experimental traumatic brain injury in the rat, male Sprague-Dawley rats were subjected to unilateral cortical impact injury. The animals were killed and examined for apoD mRNA and protein expression and for immunohistological analysis at intervals from 15 min to 14 days after injury. Increased apoD mRNA and protein levels were seen in the cortex and hippocampus ipsilateral to the injury site from 48 h to 14 days after the trauma. Immunohistological investigation demonstrated a differential pattern of apoD expression in the cortex and hippocampus, respectively: Increased apoD immunoreactivity in glial cells was detected from 2 to 3 days after the injury in cortex and hippocampus. In contrast, increased expression of apoD was seen in cortical and hippocampal neurons at later time points following impact injury. Concurrent histopathological examination using hematoxylin and eosin demonstrated dark, shrunken neurons in the cortex ipsilateral to the injury site. In contrast, no evidence of cell death was observed in the hippocampus ipsilateral to the injury site up to 14 days after the trauma. No evidence of increased apoD mRNA or protein expression or neuronal pathology by hematoxylin and eosin staining was detected in the contralateral cortex and hippocampus. Our results reveal induction of apoD expression in the cortex and hippocampus following traumatic brain injury in the rat. Our data also suggest that increased apoD expression may play an important role in cortical neuronal degeneration after brain injury in vivo. However, increased expression of apoD in the hippocampus may not necessarily be indicative of neuronal death.

A new model of retinal pigment epithelium transplantation with microspheres

OBJECTIVES

To develop a 3-dimensional carrier system for subretinal transplantation of human fetal retinal pigment epithelial (HFRPE) cells and to assess their growth pattern in the rabbit subretinal space.

METHODS

After a standard 3-port vitrectomy, HFRPE cells grown as microspheres on cross-linked fibrinogen were introduced into the subretinal space of rabbits. The eyes were studied at 7, 14, and 30 days after surgery by ophthalmoscopy and light microscopy.

RESULTS

Ophthalmoscopically, at day 7, 11 (61%) of the 18 eyes showed radiating hyperpigmentation around the transplanted HFRPE microspheres. The results of a histological examination revealed a monolayer outgrowth of HFRPE cells, overlying host retinal pigment epithelium. The control eyes revealed a patch of chorioretinal atrophy with lymphocytic infiltration around the microspheres.

CONCLUSIONS

Human fetal retinal pigment epithelial cells grown as microspheres on cross-linked fibrinogen can be successfully transplanted into the subretinal space. Cells can survive for at least 1 month and form a monolayer over the host retinal pigment epithelium cells, with a mild local inflammatory response. The difference in inflammatory responses between the eyes that underwent transplantation and the control eyes may suggest a modulating effect of the HFRPE cells on inflammation, immunity, or both. This new xenogenic model may have importance in the study of subretinal transplant cell biology and the associated immune response.

CLINICAL RELEVANCE

The results of this study may be important for better understanding of the mechanisms of retinal pigment epithelium cell behavior after transplantation. The proposed model may be applicable for future clinical and experimental investigations in the area of retinal pigment epithelium transplantation.

Cryoprecipitate: An autologous substrate for human fetal retinal pigment epithelium

PURPOSE

To harvest thin membranes from cryoprecipitates isolated from human blood donors and utilize them as substrates for the adhesion of human fetal retinal pigment epithelial (HFRPE) cells.

METHODS

Frozen human cryoprecipitates from anonymous blood donors were obtained from the blood bank. Thin cryo-membranes were harvested by their mixture with riboflavin-5-phosphate (R5P) and overnight exposure to ultra-violet light. Sheets of retinal pigment epithelium (RPE) were isolated from fetal eyes at 17-22 weeks gestational age. The sheets were subsequently attached to cryo-membranes. The morphology of the cells was examined with phase contrast and electron microscope. Cell proliferation was evaluated by their incorporation of 5-bromo-2'-deoxyuridine (BrdU). Functional viability was assessed by rod outer segment (ROS) phagocytosis.

RESULTS

Thin membrane films were made from isolated human cryoprecipitates. Isolated sheets of pure HFRPE cells were attached to the membranes. The cells maintained their cuboidal morphology and did not dedifferentiate. The cells subsequently proliferated and migrated onto the culture plate, forming cellular monolayers. The cultured cells phagocytized isolated ROS.

CONCLUSIONS

Cryoprecipitate membranes may provide an ideal source for the adhesion, cultivation, and transfer of HFRPE cells. Their autologous isolation from the recipient's blood grants an additional advantage for their application as a carrier for HFRPE transplantation into the subretinal space.

Initial clinical experience with IV tissue plasminogen activator for acute ischemic stroke: a multicenter survey. The t-PA Stroke Survey Group

We assessed initial clinical experience with IV tissue plasminogen activator (t-PA) treatment of acute ischemic stroke in a standardized retrospective survey of hospitals with experienced acute stroke treatment systems. The incidence of symptomatic intracerebral hemorrhage (ICH) was 6% (11 of 189 patients; 95% CI 3 to 11%), similar to that in the National Institute of Neurological Disorders and Stroke (NINDS) t-PA Stroke Study. Deviations from the NINDS protocol guidelines were identified in 30% of patients (56 of 189). The incidence of symptomatic ICH was 11% among patients with protocol deviations as compared with 4% in patients who were treated according to the NINDS protocol guidelines, suggesting that strict adherence to protocol guidelines is prudent.

Human fetal retinal pigment epithelial cells induce apoptosis in allogenic T-cells in a Fas ligand and PGE2 independent pathway

PURPOSE

To evaluate the inhibitory effect of human fetal retinal pigment epithelium (HFRPE) on the activation of human T-cells.

METHODS

Pure cultures of HFRPE cells were incubated with purified human T-cells in three different activation assays: 1) allogenic peripheral blood mononuclear cells; 2) OKT3 coated beads in the presence of accessory cells; and 3) stimulation with phorbol ester and phytohemagglutinin.

RESULTS

HFRPE cells suppressed the activation of T-cells in all three assays. The mechanism of HFRPE mediated T-cell suppression was apoptosis. The role of Fas ligand(FasL)/Fas-mediated T-cell suppression was excluded, since FasL protein or mRNA could not be detected on HFRPE cells with flow cytometry and by reverse transcriptase polymerase chain reaction, respectively. Additionally, the inhibitory effect of HFRPE cells could not be blocked by anti-Fas ligand or antagonistic anti-Fas antibodies. Moreover, HFRPE cells suppressed the proliferation of anti-CD3 mAb mediated T-cell proliferation of murine splenocytes isolated from lpr mice. The inhibitory effect of HFRPE cells was not PGE2 mediated, since indomethacin could not restore the T-cell activation. Although the HFRPE mediated T-cell apoptosis was cell-cell contact independent, it was not induced by secretion of TNF-alpha, TGF-beta, or IL-10. The ratio between HFRPE and T-cells had a major impact on the HFRPE's inhibitory effect.

CONCLUSIONS

HFRPE cells suppressed the activation of human T-cells by induction of T-cell apoptosis through a process that involves the secretion of soluble factors. The HFRPE mediated T-cell suppression was dependent on the ratio between HFRPE and T-cells. This undefined pathway of T-cell apoptosis may play a role in the maintenance of immune privilege in the subretinal space and may reduce the severity of the immune response after HFRPE transplantation.

Human fetal retinal pigment epithelial cells induce apoptosis in the T-cell line Jurkat

PURPOSE

To investigate the mechanism(s) involved in human fetal retinal pigment epithelium (HFRPE)-mediated T-cell death.

METHODS

Pure HFRPE cells were isolated and cultured. Normal and interferon (IFN)-gamma-activated HFRPE from early and late in vitro passages were incubated with cells from the human T-cell leukemia line Jurkat (Jkt). Cultures were pulsed with [3H]-thymidine to measure Jkt cell proliferation. Jkt cells were evaluated for apoptosis either by staining with an ethidium bromide/acridine orange mixture (AO/EB) or with Annexin V-phycoerythrin. The role of Fas ligand (FasL) molecule in HFRPE-mediated apoptosis was assessed by using a mutant Jkt cell line (DD3), which is deficient in Fas-mediated signaling. The involvement of the antiapoptotic human gene bcl-xL was determined by using Jkt cells that were stably transfected with bcl-x(L). The role of cell- cell contact in the induction of apoptosis was evaluated in a transwell system in the presence or absence of neutralizing antibodies against IFN-gamma and tumor necrosis factor (TNF)-alpha.

RESULTS

HFRPE cells inhibited the proliferation of Jkt cells by inducing apoptosis through a FasL-independent pathway. Passaging and IFN-gamma activation strengthened the inhibitory effect of HFRPE cells on the proliferation of Jkt cells. At lower HFRPE passages (P2), bcl-alphaL, overexpression rescued the HFRPE cell-mediated apoptosis. The separation of the cells by the transwell system did not affect the HFRPE cell-mediated suppression. This suppressive effect was not mediated by the secretion of IFN-gamma or TNF-alpha molecules.

CONCLUSIONS

HFRPE cells suppressed the proliferation of Jkt cells by inducing apoptosis. HFRPE cells induced a stronger inhibitory effect on Jkt cells at higher in vitro passages. The HFRPE-induced apoptosis was not mediated through the FasL/Fas pathway or through the secretion of the apoptosis-inducing cytokines IFN-gamma and TNF-alpha. The bcl-xL gene may play a role in preventing HFRPE cell-induced apoptosis in Jkt cells. These combined results suggest that the HFRPE-mediated suppression of primary T cells may also be mediated by the induction of apoptosis. Therefore, the retinal pigment epithelium may play a role in the induction of immune privilege in the subretinal space.

Biodegradable polymer film as a source for formation of human fetal retinal pigment epithelium spheroids

PURPOSE

To evaluate the attachment of human fetal rctinal pigment epithelial (HFRPE) cells to a biodegradable polymer film with subsequent formation of spheroids in vitro.

METHODS

Ten biodegradable polymer films with different compositions were examined for their physical properties and ease of manipulation under a dissecting microscope. The film with the most suitable handling characteristics was chosen, and a purely isolated sheet of HFRPE cells was attached to it. The purity of the cells was assessed by their pigmentation and expression of cytokeratin. Proliferation was assessed by incorporation of 5-bromo-2'-deoxyuridine (BrdtJ). Cellular structure was analyzed under light and electron microscopes, and the functional capability of the cells was evaluated by rod outer segment (ROS) phagocytosis.

RESULTS

The polymer film with composition 50:50 poly (DL-lactide) (PLA)/poly (DL-lactide-co-glycolide) (PLG) with an inherent viscosity of 1.03 dl/g was found to be the most suitable for handling under the microscope. Sheets of HFRPE cells attached to the polymer films within 48 hours and began to form spheroids. All the isolated cells were pigmented and expressed cytokeratin. They possessed a cuboidal morphology, numerous apical microvilli, and no sign of dedifferentiation. HFRPE cells produced extracellular matrix (collagen filaments) on their basal side, filling the cavities of the polymer film. The cells subsequently proliferated, incorporated BrdU, migrated onto the culture plate to form monolayers, and phagocytized ROS.

CONCLUSIONS

Biodegradable polymer films can be used as a scaffold for the adhesion of the HFRPE sheet and formation of spheroids. Spheroids represent a source of high density and well-differentiated HFRPE cells that are easy to transfer. Furthermore, the stricture of the membrane makes it suitable for additional applications.

Cellular response in rabbit eyes after human fetal RPE cell transplantation

BACKGROUND

This study was carried out to study inflammatory and proliferative cellular responses in the rabbit eye after subretinal transplantation of human fetal retinal pigment epithelial (HFRPE) cells.

METHODS

5-Bromo-2-deoxyuridine (BrdU)-labeled HFRPE cells were injected subretinally into rabbit eyes at three different concentrations. Macrophage, glial, and proliferative responses of the eye tissues were studied by immunohistochemistry and light microscopy at different times after the surgery.

RESULTS

In transplanted eyes, the HFRPE cells were distributed irregularly either as multilayers or monolayers. In eyes receiving high-density cell suspensions, retinal breaks were seen. No retinal breaks were noted in the eyes receiving low-density HFRPE cell suspensions. The highest intensity of inflammatory response was seen at 4-14 days after surgery, with greater expression in transplanted eyes receiving high-density cell suspensions. The host cellular response was characterized initially by local infiltration of the retina and subretinal space by macrophages and glial cells. After day 14, a decline in the number of donor cells was noted in all eyes. At later stages the host cellular response was characterized mainly by local choroidal thickening and infiltration by inflammatory cells. Proliferative response was expressed mainly by retinal cells.

CONCLUSION

Initial inflammatory and proliferative responses after the xenogenic human to rabbit HFRPE cell transplantation were expressed by retinal cells with later involvement of the choroid. Our results showed a decline in the number of donor cells starting from day 14 after the transplantation. This may suggest a possibility of rejection. The initial quantity of injected cells may be critical for the intensity of the immune and inflammatory responses.

Apolipoprotein D gene expression in the rat brain and light and electron microscopic immunocytochemistry of apolipoprotein D expression in the cerebellum of neonatal, immature and adult rats

Apolipoprotein D gene and protein expression were investigated in the rat brain and cerebellum, respectively, during development. Apolipoprotein D gene expression was first observed in embryonic day 12 rat brain, with a moderate increase in apolipoprotein D messenger RNA levels towards the later part (embryonic days 15-17) of gestation. In the postnatal rat brain, a marked induction of apolipoprotein D messenger RNA occurred at postnatal day 10, with progressively higher levels of apolipoprotein D messenger RNA observed up to postnatal day 20. Somewhat lower, but none the less high, levels of apolipoprotein D messenger RNA continued to be present in brains of adult animals. In the immature cerebellum (day 3 up to one- to two-week-old rats), there were many densely labeled apolipoprotein D-immunoreactive cells that had features of oligodendrocyte precursors. Purkinje neurons showed apolipoprotein D immunoreactivity in one- to two-week-old animals, after which there appeared to be some decrease in staining. Oligodendrocytes in the cerebella of two-week-old animals were strongly apolipoprotein D positive, with immunoreactivity declining in older animals. These results reveal a maturation-associated induction of apolipoprotein D gene expression in the rat brain, and expression of apolipoprotein D in glial (immature oligodendrocyte) cells in the immature cerebellum, followed by specific expression of apolipoprotein D in Purkinje neurons.