Identification and characterization of mesenchymal stem cells derived from the trabecular meshwork of the human eye

Mesenchymal stem cells (MSC) have been isolated from several adult human tissues. Their propensity to differentiate into cell types of connective tissue, such as osteocytes, chondrocytes, and adipocytes, suggests that MSC may function as a reserve of progenitor cells that repair and maintain healthy adult tissues. Dysfunction of the trabecular meshwork (TM), a connective tissue at the anterior region of the human eye that regulates intraocular pressure, plays a major role in the pathogenesis of glaucoma. The mechanobiology and pharmacological aspects of the TM tissue have been relatively well studied in disease states. Less well understood is if there are progenitor cells within the TM that contribute to maintenance of this tissue. In this study, we have identified and characterized an expandable population of cells that have stem cell-like properties. In particular, these cells express the markers CD73, CD90, and CD105, which are typically associated with MSC. Thus, we have named these cells TM-MSC. As further evidence that these cells are MSC, they were differentiated in vitro into adipocytes, osteocytes, and chondrocytes. Through genomic characterization, we show that TM-MSC have gene expression patterns most similar to MSC derived from other tissues. TM-MSC express genes found on adult TM tissue, suggesting that TM-MSC are progenitor cells that serve to maintain a healthy TM.

Expression profile of inflammatory cytokines in aqueous from glaucomatous eyes

PURPOSE

To determine the proinflammatory cytokine profile of aqueous humor from glaucomatous eyes.

METHODS

Aqueous humor samples were prospectively collected from 38 eyes (26 primary open angle glaucoma [POAG] and 12 primary angle closure glaucoma [PACG] eyes) of 37 medically treated glaucoma patients and 23 cataract subjects recruited in an institutional setting in this case-controlled study. The main outcome measure was to quantify the levels of 29 inflammatory cytokines in the aqueous of glaucoma and cataract subjects using a multiplexed cytokine analysis. Data on patient demographics, duration of glaucoma, preoperative intraocular pressure (IOP) as well as duration of anti-glaucoma therapy were also collected for correlation analysis.

RESULTS

Mean duration of glaucoma was 53.8 months (range 1-360 months). Aqueous obtained from the glaucoma patients showed increased concentration of interleukin (IL)-9 (p=0.032), IL-12 (p=0.003), interferon (IFN)-α (p=0.034), IFN-γ (p=0.002), monokine induced by interferon-gamma (MIG or CXCL9) (p=0.006), and IL-10 (p=0.050), compared to the cataract group. The POAG group had higher IL-12 (p=0.011), IFN-γ (p=0.005), and CXCL9 (p=0.047) levels than controls, while the PACG group had higher interleukin-8 (CXCL8) (p=0.015) and CXCL9 (p=0.023) levels than the controls. No significant correlation was observed between aqueous cytokine level and preoperative IOP and duration of glaucoma. Duration of topical Timolol and Alphagan therapy correlated negatively with CXCL8 (r=-0.588, p=0.035), respectively.

CONCLUSIONS

Primary glaucoma is associated with an aqueous inflammatory response and this is different between POAG and PACG groups. Duration of glaucoma treatment may have an effect on cytokine profile in the aqueous.

Involvement of SPARC and MMP-3 in the pathogenesis of human pterygium

PURPOSE

To investigate the expression of SPARC and matrix metalloproteinases (MMPs) in normal conjunctiva and pterygium tissues.

METHODS

This study involved paired control or uninvolved conjunctiva and pterygium tissue from 21 patients. Quantitative real-time PCR was performed to assess SPARC and MMP mRNA expression, whereas Western blot analysis was performed to assess SPARC protein levels in normal conjunctiva and pterygium tissue. Tissue localization of SPARC, extracellular matrix proteins, and MMPs were determined by immunofluorescence analyses.

RESULTS

SPARC transcript and protein levels were upregulated in pterygium compared with normal conjunctiva. Immunofluorescence analyses showed localization of SPARC to the epithelial basement membrane and stroma of normal conjunctiva tissue. Increased SPARC in the pterygium stroma colocalized partially with elevated collagen I, fibronectin, α-SMA, and MMP-3. SPARC and MMP-3 also colocalized in the pterygium epithelium.

CONCLUSIONS

SPARC was upregulated in pterygium and may collaborate with increased MMP-3 in some patients to account for many of the phenotypic properties characteristic of pterygium.

Nanomedicine for glaucoma: liposomes provide sustained release of latanoprost in the eye

Purpose:

To report the development and therapeutic evaluation of a liposomal nanocarrier for sustained release of latanoprost, in the rabbit eye.

Methods:

We fabricated latanoprost-loaded egg-phosphatidylcholine (EggPC) liposomes using the film hydration technique. The delivery vehicles were nano-sized (Z avg = 109 ± 18 nm), had a narrow poly dispersity index (PDI = 0.19 ± 0.04), and a very high loading efficiency (94% ± 5%). Based on in vitro data, we evaluated this formulation for lowering intraocular pressure (IOP) in rabbit eyes. Following a single subconjunctival injection of the latanoprost loaded formulation, the eyes were clinically monitored and the IOP recorded.

Results:

Latanoprost-loaded EggPC liposomes demonstrated a high drug/lipid mole ratio of 0.181, remained stable for at least 6 months on storage (4°C), and at least 1 month at 25°C. A slow and sustained release of 60% of latanoprost was achieved by 14 days in the in vitro release study. The same formulation demonstrated a greater sustained IOP lowering effect compared with daily administration of topical latanoprost beyond 90 days (4.8 ± 1.5 vs 2.5 ± 0.9 mmHg; P < 0.001). No signs of inflammation were evident in the eyes from slit-lamp examination analysis.

Conclusion:

The loading required for a long-term sustained delivery of latanoprost for up to 90 days in the rabbit eyes was achieved with EggPC liposomes. A single injection of latanoprost-loaded EggPC liposomes can lower the IOP for up to 90 days, with a greater IOP lowering effect than daily topical administration of latanoprost.

Evaluation of sustained release of PLC-loaded prednisolone acetate microfilm on postoperative inflammation in an experimental model of glaucoma filtration surgery

PURPOSE

To evaluate the effect of a biodegradable microfilm with sustained release of prednisolone acetate (PA) on postoperative wound healing after experimental glaucoma filtration surgery (GFS).

METHODS

Biodegradable microfilms composed of poly (D-, L-lactide-co-caprolactone) (PLC) were fabricated and then pre-loaded PA-20% total weight. Fourteen New Zealand White rabbits were randomly divided into 3 treatment groups: GFS alone (n=4), GFS with PLC microfilms (n=4) and GFS with PA-loaded microfilm (n=6). Microfilms were inserted subconjunctivally, adjacent to the filtering surgical site. We monitored all eyes with slit-lamp examination, bleb photography and anterior segment optical coherence tomography (AS-OCT). Histology with immunohistochemistry was performed to determine the presence of any inflammation.

RESULTS

Prednisolone acetate 20%-loaded microfilms exhibited steady, sustained release in vitro. Eyes implanted with PA-loaded microfilms showed a significantly better bleb survival (100% vs. 37.5%, p<0.001) and reduced bleb vascularity (58%; 95% CI 54-62% vs. 30%; 95% CI 23-37%, p=0.001) compared to the control at 30 days postoperatively. Histology and immunohistochemistry demonstrated less T-cell infiltration in the eye implanted with PA-loaded microfilms.

CONCLUSION

Subconjunctival insertion of a PA-loaded biodegradeable microfilm exhibit sustained release of PA to reduce postoperative inflammation and prolong bleb survival in rabbit GFS.

Sustained release of an anti-glaucoma drug: demonstration of efficacy of a liposomal formulation in the rabbit eye

Topical medication remains the first line treatment of glaucoma; however, sustained ocular drug delivery via topical administration is difficult to achieve. Most drugs have poor penetration due to the multiple physiological barriers of the eye and are rapidly cleared if applied topically. Currently, daily topical administration for lowering the intra-ocular pressure (IOP), has many limitations, such as poor patient compliance and ocular allergy from repeated drug administration. Poor compliance leads to suboptimal control of IOP and disease progression with eventual blindness. The delivery of drugs in a sustained manner could provide the patient with a more attractive alternative by providing optimal therapeutic dosing, with minimal local toxicity and inconvenience. To investigate this, we incorporated latanoprost into LUVs (large unilamellar vesicles) derived from the liposome of DPPC (di-palmitoyl-phosphatidyl-choline) by the film hydration technique. Relatively high amounts of drug could be incorporated into this vesicle, and the drug resides predominantly in the bilayer. Vesicle stability monitored by size measurement and DSC (differential scanning calorimetry) analysis showed that formulations with a drug/lipid mole ratio of about 10% have good physical stability during storage and release. This formulation demonstrated sustained release of latanoprost in vitro, and then tested for efficacy in 23 rabbits. Subconjunctival injection and topical eye drop administration of the latanoprost/liposomal formulation were compared with conventional daily administration of latanoprost eye drops. The IOP lowering effect with a single subconjunctival injection was shown to be sustained for up to 50 days, and the extent of IOP lowering was comparable to daily eye drop administration. Toxicity and localized inflammation were not observed in any treatment groups. We believe that this is the first demonstration, in vivo, of sustained delivery to the anterior segment of the eye that is safe and efficacious for 50 days.

Blindness and long-term progression of visual field defects in chinese patients with primary angle-closure glaucoma

PURPOSE

To investigate the long-term rates of blindness and visual field (VF) progression in treated primary angle-closure glaucoma (PACG) patients.

DESIGN

Retrospective observational case series.

METHODS

PACG patients with ≥10 years of follow-up were analyzed. All VFs (static automated perimetry, central 24-2 threshold test) performed were reviewed and reliable VFs (fixation losses <20%, false positives and false negatives <33%) were scored using the Advanced Glaucoma Intervention Study (AGIS) system. Progression of a VF defect was defined as a change of ≥4 from baseline on 2 consecutive VF tests.

RESULTS

From the 137 eyes of 87 patients with PACG with ≥10 years of follow-up identified, 6% and 30.1% were blind based on initial visual acuity (VA) and VF criteria respectively and 12.0% had an initial AGIS score of 20; these were excluded. Eighty-three eyes from 57 patients (all Chinese, mean age 59.9 ± 8.2 years, 67.5% female) were analyzed. The mean AGIS score was 5.14 ± 4.37 at baseline. VF deterioration was detected in 27 eyes (32.5%) of 21 patients, with 4.8% and 7.2% of eyes progressing to blindness based on VA and VF criteria respectively. On Cox regression, eyes with VF progression had higher mean overall IOP (P < .001), and higher prevalence of previous acute angle closure (AAC, P = .008).

CONCLUSIONS

Over 10 years, a third of PACG patients were found to have VF progression, with 7% progressing to blindness while on treatment. Eyes with higher mean overall IOP and a history of previous AAC were more likely to have VF progression.

Aberrant DNA methylation of matrix remodeling and cell adhesion related genes in pterygium

Background

Pterygium is a common ocular surface disease characterized by abnormal epithelial and fibrovascular proliferation, invasion, and matrix remodeling. This lesion, which migrates from the periphery to the center of the cornea, impairs vision and causes considerable irritation. The mechanism of pterygium formation remains ambiguous, and current treatment is solely surgical excision, with a significant risk of recurrence after surgery. Here, we investigate the role of methylation in DNA sequences that regulate matrix remodeling and cell adhesion in pterygium formation.

Methodology/Principal Findings

Pterygium and uninvolved conjunctiva samples were obtained from the same eye of patients undergoing surgery. The EpiTYPER Sequenom technology, based on differential base cleavage and bisulfite sequencing was used to evaluate the extent of methylation of 29 matrix and adhesion related genes. In pterygium, three CpG sites at −268, −32 and −29 bp upstream of transglutaminase 2 (TGM-2) transcription initiation were significantly hypermethylated (p<0.05), whereas hypomethylation was detected at CpGs +484 and +602 bp downstream of matrix metalloproteinase 2 (MMP-2) transcription start site, and −809, −762, −631 and −629 bp upstream of the CD24 transcription start site. RT-qPCR, western blot and immunofluorescent staining showed that transcript and protein expression were reduced for TGM-2 and increased for MMP-2 and CD24. Inhibition of methylation in cultured conjunctival epithelial cells increased these transcripts.

Conclusions/Significance

We found regions of aberrant DNA methylation which were consistent with alteration of TGM-2, MMP-2, and CD24 transcript and protein expression, and that inhibition of methylation in cultured cells can increase the expression of these genes. Since these genes were related to cell adhesion and matrix remodeling, dysregulation may lead to fibroblastic and neovascular changes and pterygium formation. These results have implications for the prognostication of pterygium in clinical practice, for example, detection of epigenetic changes may have a role in predicting post surgical recurrence of aggressive lesions.

Validation of the glaucoma filtration surgical mouse model for antifibrotic drug evaluation

Glaucoma is a progressive optic neuropathy, which, if left untreated, leads to blindness. The most common and most modifiable risk factor in glaucoma is elevated intraocular pressure (IOP), which can be managed surgically by filtration surgery. The postoperative subconjunctival scarring response, however, remains the major obstacle to achieving long-term surgical success. Antiproliferatives such as mitomycin C are commonly used to prevent postoperative scarring. Efficacy of these agents has been tested extensively on monkey and rabbit models of glaucoma filtration surgery. As these models have inherent limitations, we have developed a model of glaucoma filtration surgery in the mouse. We show, for the first time, that the mouse model typically scarred within 14 d, but when augmented with mitomycin C, more animals maintained lower intraocular pressures for a longer period of time concomitant with prolonged bleb survival to beyond 28 d. The morphology of the blebs following mitomycin C treatment also resembled well-documented clinical observations, thus confirming the validity and clinical relevance of this model. We demonstrate that the antiscarring response to mitomycin C is likely to be due to its effects on conjunctival fibroblast proliferation, apoptosis and collagen deposition and the suppression of inflammation. Indeed, we verified some of these properties on mouse conjunctival fibroblasts cultured in vitro. These data support the suitability of this mouse model for studying the wound healing response in glaucoma filtration surgery, and as a potentially useful tool for the in vivo evaluation of antifibrotic therapeutics in the eye.

SPARC deficiency results in improved surgical survival in a novel mouse model of glaucoma filtration surgery

Glaucoma is a disease frequently associated with elevated intraocular pressure that can be alleviated by filtration surgery. However, the post-operative subconjunctival scarring response which blocks filtration efficiency is a major hurdle to the achievement of long-term surgical success. Current application of anti-proliferatives to modulate the scarring response is not ideal as these often give rise to sight-threatening complications. SPARC (secreted protein, acidic and rich in cysteine) is a matricellular protein involved in extracellular matrix (ECM) production and organization. In this study, we investigated post-operative surgical wound survival in an experimental glaucoma filtration model in SPARC-null mice. Loss of SPARC resulted in a marked (87.5%) surgical wound survival rate compared to 0% in wild-type (WT) counterparts. The larger SPARC-null wounds implied that aqueous filtration through the subconjunctival space was more efficient in comparison to WT wounds. The pronounced increase in both surgical survival and filtration efficiency was associated with a less collagenous ECM, smaller collagen fibril diameter, and a loosely-organized subconjunctival matrix in the SPARC-null wounds. In contrast, WT wounds exhibited a densely packed collagenous ECM with no evidence of filtration capacity. Immunolocalization assays confirmed the accumulation of ECM proteins in the WT but not in the SPARC-null wounds. The observations in vivo were corroborated by complementary data performed on WT and SPARC-null conjunctival fibroblasts in vitro. These findings indicate that depletion of SPARC bestows an inherent change in post-operative ECM remodeling to favor wound maintenance. The evidence presented in this report is strongly supportive for the targeting of SPARC to increase the success of glaucoma filtration surgery.

Calcium-binding S100 protein expression in pterygium

PURPOSE

Pterygium is an ocular surface disease of unknown etiology associated with epithelial and fibrovascular outgrowth from the conjunctiva onto the cornea. S100 proteins are calcium-activated signaling proteins that interact with other proteins to modulate biological functions such as cell migration, proliferation, and differentiation. The aim of this study was to investigate the presence of various S100 proteins in pterygium compared to normal conjunctiva.

METHODS

Immunofluorescent staining using antibodies against S100A4, S100A6, S100A8, S100A9, and S100A11 were conducted to investigate the expression and tissue distribution. S100 protein secretions and expressions were confirmed using western blot and quantitative real-time polymerase chain reaction (RT-PCR), respectively.

RESULTS

Immunofluorescent staining demonstrated the presence of S100A4, S100A6, S100A8, S100A8, S100A9, and S100A11 in both conjunctival and pterygial epithelium. No significant difference was found in the localization and expression of S100A4. In both conjunctiva and pterygium, S100A4-positive cells were found in superficial and suprabasal layers. S100A6 expression was strong in the superficial layer of pterygium epithelium but relatively weaker in the suprabasal and superficial cells of normal conjunctiva epithelium. S100A8 and S100A9 were localized in the superficial layer of both pterygium and normal conjunctiva epithelium, with higher levels in pterygium than uninvolved conjunctiva. S100A11 was expressed in the basal cells of conjunctival epithelium but in the suprabasal layers of pterygium epithelium. Western blot and RT-PCR confirmed the presence of S100A4, S100A6, S100A8, S100A9, and S100A11 in pterygium and conjunctiva tissue.

CONCLUSIONS

Higher levels of S100A6, S100A8, and S100A9 expressions were detected in the pterygium tissue relative to normal conjunctiva. In addition, a distinct alteration of localization of S100A11 expression was observed in pterygium epithelium compared to the conjunctiva. Therefore, these S100 proteins may be associated with the formation of pterygium.

The singapore 5-Fluorouracil trabeculectomy study: effects on intraocular pressure control and disease progression at 3 years

PURPOSE

To report 3-year results of a randomized, controlled trial comparing the use of a single application of 5-fluorouracil (5-FU) with placebo in trabeculectomy surgery.

DESIGN

Prospective, randomized, double-blinded treatment trial.

PARTICIPANTS

Two hundred forty-three Asian patients with primary open-angle or primary angle-closure glaucoma undergoing primary trabeculectomy.

METHODS

One eye of each patient was randomized to receive either intraoperative 5-FU or normal saline (placebo) during trabeculectomy.

MAIN OUTCOME MEASURES

Primary outcome measure was the level of intraocular pressure (IOP). Secondary outcomes were progression of visual field loss, rates of adverse events, and interventions after surgery.

RESULTS

Of the 288 eligible patients, 243 were enrolled and 228 completed 3 years follow-up; 120 patients received 5-FU and 123 received placebo. Trial failure, according to predefined IOP criteria, was lower in the 5-FU group compared with the placebo group, although the difference was only significant with a failure criterion of IOP >17 mmHg (P = 0.0154). There was no significant difference in progression of optic disc and/or visual field loss over 36 months between 5-FU and placebo (relative risk [RR], 0.67; 95% confidence interval [CI], 0.34-1.31; P = 0.239). Uveitis occurred more often in the 5-FU-treated group (14/115 [12%] vs 5/120 [4%]; P = 0.032).

CONCLUSIONS

This is the first masked, prospective, randomized trial reporting the effect of adjunctive 5-FU in trabeculectomy surgery in an East Asian population. The trial shows that an increased success rate can be achieved for several years after a single intraoperative treatment with 5-FU. We conclude that 5-FU is relatively safe and can be routinely used in low-risk East Asian patients.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Increased SPARC expression in primary angle closure glaucoma iris

PURPOSE

SPARC (secreted protein, acidic, and rich in cysteine) is involved in extracellular matrix (ECM) organization. The purpose of this study was to evaluate the expression of SPARC in iris tissue from primary angle closure glaucoma (PACG) eyes.

METHODS

Iris tissue was obtained from peripheral iridectomies performed during trabeculectomy surgery in nine PACG and 16 primary open-angle glaucoma (POAG) eyes at the Singapore National Eye Centre. Three non-glaucoma control iris specimens were obtained from patients who underwent Descemet's stripping automated endothelial keratoplasty (DSAEK) procedure. SPARC and collagen I expression were quantified by real-time polymerase chain reaction (PCR). The histological distribution of collagen I and III in the iris stroma was determined using picrosirius red polarization. Density of the iris stromal vasculature was also calculated.

RESULTS

The mean age was 68.9+/-10.9 years and 65.7+/-12.2 years in POAG and PACG groups, respectively. The PACG iris expressed SPARC 13.6-fold more and collagen I 5.2 fold more compared to non-glaucoma control iris. The PACG iris also demonstrated 3.3 fold higher SPARC and 2.0 fold higher collagen I expression relative to the POAG iris. The density of collagen I was greater in PACG eyes than in POAG and control eyes (p<0.001). The mean density of iris stromal blood vessels per micron square area was similar in all three groups.

CONCLUSIONS

SPARC was significantly increased in the PACG iris. The data suggest that SPARC could play a role in the development of PACG by influencing the biomechanical properties of the iris through a change in ECM organization.

Photorealistic virtual anatomy based on Chinese Visible Human data

Virtual reality based learning of human anatomy is feasible when a database of 3D organ models is available for the learner to explore, visualize, and dissect in virtual space interactively. In this article, we present our latest work on photorealistic virtual anatomy applications based on the Chinese Visible Human (CVH) data. We have focused on the development of state-of-the-art virtual environments that feature interactive photo-realistic visualization and dissection of virtual anatomical models constructed from ultra-high resolution CVH datasets. We also outline our latest progress in applying these highly accurate virtual and functional organ models to generate realistic look and feel to advanced surgical simulators.

Neuroradiological findings in atypical teratoid/rhabdoid tumor of the central nervous system

PURPOSE

To evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) findings of atypical teratoid tumor/rhabdoid tumor (AT/RT) of the central nervous system (CNS).

MATERIAL AND METHODS

Twenty cases of CNS AT/RT have been found over the past 23 years in our hospital; these involving 11 boys and 9 girls whose mean age at diagnosis was 5.5 years. Their clinical data, the CT, and MRI findings were reviewed retrospectively.

RESULTS

AT/RT was located in the cerebellum in 15 cases. Four cases arose from the supratentorial region, while only one occurred primarily in the lumbar spinal cord. Almost all cases revealed heterogeneous intensity and heterogeneous enhancement. Peripheral cystic components were common. Survival time ranged from 2 months to 3 years, with a mean survival of 11.6 months.

CONCLUSION

Most cases of AT/RT are located in the cerebellum. The radiologic manifestations are non-specific. The diagnosis mainly depends on the pathologic findings. However, AT/RT should still remain in the differential diagnosis of brain tumors in young children, especially those located in the cerebellar hemisphere and with eccentric cysts.

Magnetoencephalographic yield of interictal spikes in temporal lobe epilepsy. Comparison with scalp EEG recordings

To compare magnetoencephalography (MEG) with scalp electroencephalography (EEG) in the detection of interictal spikes in temporal lobe epilepsy (TLE), we simultaneously recorded MEG and scalp EEG with a whole-scalp neuromagnetometer in 46 TLE patients. We visually searched interictal spikes on MEG and EEG channels and classified them into three types according to their presentation on MEG alone (M-spikes), EEG alone (E-spikes), or concomitantly on both modalities (M/E-spikes). The M-spikes and M/E-spikes were localized with MEG equivalent current dipole modeling. We analyzed the relative contribution of MEG and EEG in the overall yield of spike detection and also compared M-spikes with M/E-spikes in terms of dipole locations and strengths. During the 30- to 40-min MEG recordings, interictal spikes were obtained in 36 (78.3%) of the 46 patients. Among the 36 patients, most spikes were M/E-spikes (68.3%), some were M-spikes (22.1%), and some were E-spikes (9.7%). In comparison with EEG, MEG gave better spike yield in patients with lateral TLE. Sources of M/E- and M-spikes were situated in the same anatomical regions, whereas the average dipole strength was larger for M/E- than M-spikes. In conclusion, some interictal spikes appeared selectively on either MEG or EEG channels in TLE patients although more spikes were simultaneously identified on both modalities. Thus, simultaneous MEG and EEG recordings help to enhance spike detection. Identification of M-spikes would offer important localization of irritative foci, especially in patients with lateral TLE.

MRI of muscular hamartoma of the breast

Muscular hamartoma is a well-demarcated tumour composed of smooth muscle and adipose tissue. We report the MRI findings of a patient with benign breast neoplasm. To the best of our knowledge, its appearance has not been previously reported.

Power spectrum analysis of heart rate variability in children with epilepsy

OBJECT

Children with epilepsy have been found to be at increased risk of death during childhood. Sudden unexpected death (SUDEP) has accounted for at least 12% of deaths of children with epilepsy. The exact mechanisms of SUDEP are unknown; however, theories suggested have, to date, focused on autonomic instability. The purpose of this study was to investigate autonomic function in children with chronic epilepsy by means of power spectrum analysis of heart rate variability.

METHODS

Thirty patients with epilepsy and 30 control subjects, all between the ages of 4 and 10 years, were enrolled in this study. Power spectrum analysis of heart rate variability (HRV) was performed under standardized conditions after the patients had rested for 15 min. Each patient was tested in a supine position first and then again in a head-up tilted position, with 15 min between the two tests.

RESULTS

There was no significant difference between the low-frequency component (LF) and the high-frequency component (HF) of heart rate variability, or the LF/HF ratio, between the study and control groups, whether the test subjects were in the supine or the head-up tilt position. In the control group, however, the subjects showed a significantly greater LF component and a smaller HF component of heart rate variability, and a greater LF/HF ratio in the head-up position than in the supine position. This implies a normal sympathovagal balance. This phenomenon was not observed in the study group. This implies that the modulating effects on autonomic function deriving from the hemisphere were probably disturbed, owing to the brain lesions that each of the study group patients had already sustained.

CONCLUSIONS

A disturbed balance of activity between the sympathetic and parasympathetic nervous system might result from the loss of hemispheric influence in patients with epilepsy. Nevertheless, further investigation is clearly necessary to ascertain the possible association of this disturbed balance with SUDEP. Further investigation is also needed to establish the exact location of the region in the brain that gives rise to this modulating influence.

Predictors of maternal depression for families having a child with epilepsy

The purpose of this study was to use a descriptive correlational design to examine the relationship among maternal uncertainty, boundary ambiguity and depression in families having a child with epilepsy. Three hundred and twenty-four mothers from the child epilepsy day-clinics of three teaching hospitals in Taiwan participated in this study. Data collection was performed by well-trained research assistants who helped mothers fill out the well-developed Chinese version of the Parental Perception of Uncertainty Scale, the Boundary Ambiguity scale, and the Beck Depression Inventory. Uncertainty was positively associated with boundary ambiguity and depression. Boundary ambiguity was positively associated with depression. Stepwise regression analysis demonstrated that boundary ambiguity, uncertainty and mother's age are predictors of a mother's depression which account for 21.49% of the total variance of depression. The results provide a scientific knowledge base for nursing interventions that aim to provide clear information about the child's illness and help to establish appropriate patterns of parent-child interaction in terms of maintaining family boundary integrity and mothers' functional adaptability.

Electromyographic evaluation in children with spina bifida

BACKGROUND

It is controversial to predict ambulation potential using neurological level or specific pattern of muscle strength in patients with spina bifida. We attempted to analyze the relationship between the mobility outcome and its influencing factors utilizing electromyography to study motor unit activity in lower limbs. A subsidiary aim was to evaluate the external anal sphincter with electromyography and to determine the relevant factors of bowel and bladder functions.

METHODS

Among 156 patients with spina bifida who had received electromyographic examination and were followed at the out-patient clinic between 1998 and 2000, functional assessment with Pediatric Evaluation of Disability Inventory (PEDI) was applied in 47 randomly selected patients. Other assessments included clinical neurological examination, bowel and bladder function survey, and ambulation evaluation. We correlated the parameters of electromyography with the ambulatory ability and PEDI scores. The innervation of external sphincter was compared between groups with or without neurogenic bowel or bladder dysfunction.

RESULTS

The innervations of hip adductor and quadriceps were found to correlate with walking ability (p < 0.01); above muscles as well as anterior tibialis, and gastrocnemius were related to PEDI scores (p < 0.01). The neurological level still manifested correlation with walking ability (p < 0.05) and PEDI scores (p < 0.01). Both denervation potentials and recruitment pattern were important parameters for ambulation and mobility prediction. Significant difference was obtained in denervation patentials of sphincter within bowel groups (p = 0.036) and bladder groups (p = 0.016).

CONCLUSIONS

Both traditional neurological level and specific muscle innervation exert crucial influence on walking and mobility functions. Electromyographic assessment demonstrates its contribution in prediction of functional outcome in spina bifida.

A comparative MR and pathological study on fetal CNS disorders

OBJECT

We used MR after sonography to help us in prenatal counseling in 58 complicated pregnancies from 1998 to 2000.

METHODS

All fetal MR examinations were undertaken with a 1.5-T magnet using a body-phased-array coil and an ultrafast imaging technique, half-Fourier single-shot turbo spin-echo (HASTE). Twelve fetuses were found to have major anomalies, and in each of these cases either delivery was induced or the pregnancy was terminated. In 6 of the fetuses, with anomalies of the central nervous system, postmortem examinations were then performed after they failed to survive, and these constitute the patient sample investigated in the current study. The fetal gestational ages in these 6 cases ranged from 24 to 32 weeks. MR imaging demonstrated morphological details of the anomalies. They were: alobar holoprosencephaly in 2, middle interhemispheric fusion in 1, alobar holoprosencephaly with Dandy-Walker malformations in 1, a Dandy-Walker variant in 1 and twin-twin transfusion syndrome with hypoxic-ischemic injury to the brain in 1.

CONCLUSIONS

Postmortem examinations confirmed the MR diagnoses, and these observations support us in improving our understanding of the pathogenesis of fetal CNS anomalies.