Pelvic inlet area is associated with birth mode.

INTRODUCTION: To determine whether a pelvis is wide enough for spontaneous delivery has long been the subject of obstetric research. A number of variables have been proposed as predictors, all with limited accuracy. In this study, we use a novel three-dimensional (3D) method to measure the female pelvis and assess which pelvic features influence birth mode. We compare the 3D pelvic morphology of women who delivered vaginally, women who had cesarean sections, and nulliparous women. The aim of this study is to identify differences in pelvic morphology between these groups. MATERIAL AND METHODS: This observational study included women aged 50 years and older who underwent a CT scan of the pelvis for any medical indication. We recorded biometric data including height, weight, and age, and obtained the obstetric history. The bony pelvis was extracted from the CT scans and reconstructed in three dimensions. By placing 274 landmarks on each surface model, the pelvises were measured in detail. The pelvic inlet was measured using 32 landmarks. The trial was registered at the German Clinical Trials Register DRKS (DRKS00017690). RESULTS: For this study, 206 women were screened. Exclusion criteria were foreign material in the bony pelvis, unknown birth mode, and exclusively preterm births. Women who had both a vaginal birth and a cesarean section were excluded from the group comparison. We compared the pelvises of 177 women between three groups divided by obstetric history: vaginal births only (n = 118), cesarean sections only (n = 21), and nulliparous women (n = 38). The inlet area was significantly smaller in the cesarean section group (mean = 126.3 cm2 ) compared with the vaginal birth group (mean = 134.9 cm2 , p = 0.002). The nulliparous women were used as a control group: there was no statistically significant difference in pelvic inlet area between the nulliparous and vaginal birth groups. CONCLUSIONS: By placing 274 landmarks on a pelvis reconstructed in 3D, a very precise measurement of the morphology of the pelvis is possible. We identified a significant difference in pelvic inlet area between women with vaginal delivery and those with cesarean section. A unique feature of this study is the method of measurement of the bony pelvis that goes beyond linear distance measurements as used in previous pelvimetric studies.

Cloning, function, and localization of human, canine, and Drosophila ZIP10 (SLC39A10), a Zn2+ transporter.

Zinc (Zn2+) is the second most abundant trace element, but is considered a micronutrient, as it is a cofactor for many enzymes and transcription factors. Whereas Zn2+ deficiency can cause cognitive immune or metabolic dysfunction and infertility, excess Zn2+ is nephrotoxic. As for other ions and solutes, Zn2+ is moved into and out of cells by specific membrane transporters: ZnT, Zip, and NRAMP/DMT proteins. ZIP10 is reported to be localized at the apical membrane of renal proximal tubules in rats, where it is believed to play a role in Zn2+ import. Renal regulation of Zn2+ is of particular interest in light of growing evidence that Zn2+ may play a role in kidney stone formation. The objective of this study was to show that ZIP10 homologs transport Zn2+, as well as ZIP10, kidney localization across species. We cloned ZIP10 from dog, human, and Drosophila ( CG10006), tested clones for Zn2+ uptake in Xenopus oocytes and localized the protein in renal structures. CG10006, rather than foi (fear-of-intimacy, CG6817) is the primary ZIP10 homolog found in Drosophila Malpighian tubules. The ZIP10 antibody recognizes recombinant dog, human, and Drosophila ZIP10 proteins. Immunohistochemistry reveals that ZIP10 in higher mammals is found not only in the proximal tubule, but also in the collecting duct system. These ZIP10 proteins show Zn2+ transport. Together, these studies reveal ZIP10 kidney localization, a role in renal Zn2+ transport, and indicates that CG10006 is a Drosophila homolog of ZIP10.

Delayed interval delivery in multiple gestations: the Munich experience.

OBJECTIVE: To evaluate delayed interval deliveries in multiple gestations in regard of delayed interval and neonatal survival and to provide a protocol. METHODS: Data of multiple pregnancies with delayed interval delivery at a tertiary maternity unit between 2002 and 2017 were collected. Contraindications for evaluation of a delay of the delivery of the remaining child were: severe maternal blood loss, poor maternal general condition, preeclampsia, placental abruption, fetal distress, serious congenital malformations of the remaining child, chorioamnionitis, and premature rupture of membranes of the second fetus. A total of 14 cases was included in this retrospective monocentric analysis. RESULTS: The cohort comprised nine twin and five triplet pregnancies. Mean gestational age at delivery of the first fetus was 21 + 6 and 26 + 0 of the retained fetus, respectively. The earliest delivery of the first fetus was at 15 + 2 weeks. The mean interval of the delay was 29.3 days (2-82 days). Mortality of the first fetuses was 53.3%, while it was 17.6% for the retained fetuses. Maternal outcome was good in general: two cases of major blood loss occurred with the necessity of a blood transfusion. CONCLUSION: Delayed interval delivery is a reasonable approach in cases of an imminent preterm birth in multiple gestations which can be performed with a good fetal outcome and limited maternal risks. The situation when this procedure may be an option always comes unexpected. Therefore, the team of perinatologists should keep it in mind as one potential therapeutic approach. In addition, a standard protocol for the procedure should be established in the perinatal center.

Reassessment of the Transport Mechanism of the Human Zinc Transporter SLC39A2.

The human zinc transporter SLC39A2, also known as ZIP2, was shown to mediate zinc transport that could be inhibited at pH <7.0 and stimulated by HCO3-, suggesting a Zn2+/HCO3- cotransport mechanism [Gaither, L. A., and Eide, D. J. (2000) J. Biol. Chem. 275, 5560-5564]. In contrast, recent experiments in our laboratory indicated that the functional activity of ZIP2 increases at acidic pH [Franz, M. C., et al. (2014) J. Biomol. Screening 19, 909-916]. The study presented here was therefore designed to reexamine the findings about the pH dependence and to extend the functional characterization of ZIP2. Our current results show that ZIP2-mediated transport is modulated by extracellular pH but independent of the H+ driving force. Also, in our experiments, ZIP2-mediated transport is not modulated by extracellular HCO3-. Moreover, a high extracellular [K+], which induces depolarization, inhibited ZIP2-mediated transport, indicating that the transport mechanism is voltage-dependent. We also show that ZIP2 mediates the uptake of Cd2+ ( Km ∼ 1.57 µM) in a pH-dependent manner ( KH+ ∼ 66 nM). Cd2+ transport is inhibited by extracellular [Zn2+] (IC50 ∼ 0.32 µM), [Cu2+] (IC50 ∼ 1.81 µM), and to a lesser extent [Co2+], but not by [Mn2+] or [Ba2+]. Fe2+ is not transported by ZIP2. Accordingly, the substrate selectivity of ZIP2 decreases in the following order: Zn2+ > Cd2+ ≥ Cu2+ > Co2+. Altogether, we propose that ZIP2 is a facilitated divalent metal ion transporter that can be modulated by extracellular pH and membrane potential. Given that ZIP2 expression has been reported in acidic environments [Desouki, M. M., et al. (2007) Mol. Cancer 6, 37; Inoue, Y., et al. (2014) J. Biol. Chem. 289, 21451-21462; Tao, Y. T., et al. (2013) Mol. Biol. Rep. 40, 4979-4984], we suggest that the herein described H+-mediated regulatory mechanism might be important for determining the velocity and direction of the transport process.

Maternal and neonatal omentin-1 levels in gestational diabetes.

PURPOSE: To evaluate the effect of gestational diabetes on omentin-1 in maternal and cord plasma. As a potent mediator of insulin resistance, Omentin-1, an adipokine derived from human adipose and placental tissue, may be an important player in the pathophysiology of gestational diabetes. METHODS: This was a prospective case-control study. The study included 96 women with gestational diabetes and 96 pregnant women without. Omentin-1 was measured at the time of the oral glucose tolerance test, at 32 weeks in maternal plasma and right after delivery in umbilical cord blood by ELISA assay. RESULTS: Over a period of 2 years, 200 patients were enrolled. Omentin-1 levels did not significantly differ between both groups throughout the pregnancy: omentin-1 levels were 157 ± 83 ng/ml in women with gestational diabetes and 158 ± 93 ng/ml in women without gestational diabetes (p = 0.94) at time of the oral glucose tolerance test and 118 ± 77 ng/ml in women with diabetes and 150 ± 89 ng/ml in women without (p = 0.12) at 32 weeks, respectively. Both groups showed a decrease in omentin-1 levels throughout pregnancy, with a more pronounced decrease in diabetic women (13 ± 53 versus 4 ± 48 ng/ml; p = 0.5). Neonatal omentin-1 levels were significantly lower in offspring of diabetic mothers: 106 ± 61 versus 134 ± 45 ng/ml (p = 0.03). CONCLUSIONS: There was no significant difference in omentin-1 levels between healthy and diabetic mothers throughout the pregnancy. However, we found significantly lower omentin-1 levels in offspring of diabetic mothers. This may indicate a risk for the development of insulin resistance in later life.

MR pelvimetry: prognosis for successful vaginal delivery in patients with suspected fetopelvic disproportion or breech presentation at term.

PURPOSE: The purpose of this study was to correlate MR pelvimetric pelvic inlet measurements with mode of delivery and neonatal outcome in patients with suspected fetopelvic disproportion or breech presentation. METHODS: For this retrospective monocentric study, 237 consecutive MR pelvimetry reports (1999-2016) of pregnant women due to either suspected fetopelvic disproportion, pelvic deformation after trauma, or persistent breech presentation were retrieved from the radiologic database and matched with corresponding information from the obstetric database. RESULTS: Of 223 included women, 95 (42.6%) underwent planned cesarean section (pCS) and 128 (57.4%) underwent a trial of vaginal labour (TOL), of whom 93 (72.7%) delivered vaginally. Vaginal delivery was successful in 45 out of 64 (70.3%) cephalic cases and in 48 out of 64 (75.0%) breech cases. We found statistically significant differences in conjugata vera obstetrica (CV) and diameter transversalis (DT) between the groups TOL and pCS (CV: 12.5 ± 1.0 vs 12.1 ± 1.2 cm, p value 0.001; DT: 13.3 ± 0.9 vs 12.7 ± 0.9 cm, p value <0.001, respectively). However, there was no significant difference between successful VD and cesarean section after TOL (CV: 12.5 ± 0.9 vs 12.3 ± 1.1 cm, p value 0.194; DT: 13.4 ± 0.9 vs 13.2 ± 0.9 cm, p value 0.358, respectively). CONCLUSIONS: In our cohort, MR pelvimetry was a useful tool for prepartal assessment of the female pelvis in the selection of TOL candidates. Yet, it does not seem to yield additional predictive value for women with a previous vaginal delivery.

The predictive value of quantitative fibronectin testing in combination with cervical length measurement in symptomatic women.

BACKGROUND: The combination of the qualitative fetal fibronectin test and cervical length measurement has a high negative predictive value for preterm birth within 7 days; however, positive prediction is poor. A new bedside quantitative fetal fibronectin test showed potential additional value over the conventional qualitative test, but there is limited evidence on the combination with cervical length measurement. OBJECTIVE: The purpose of this study was to compare quantitative fetal fibronectin and qualitative fetal fibronectin testing in the prediction of spontaneous preterm birth within 7 days in symptomatic women who undergo cervical length measurement. STUDY DESIGN: We performed a European multicenter cohort study in 10 perinatal centers in 5 countries. Women between 24 and 34 weeks of gestation with signs of active labor and intact membranes underwent quantitative fibronectin testing and cervical length measurement. We assessed the risk of preterm birth within 7 days in predefined strata based on fibronectin concentration and cervical length. RESULTS: Of 455 women who were included in the study, 48 women (11%) delivered within 7 days. A combination of cervical length and qualitative fibronectin resulted in the identification of 246 women who were at low risk: 164 women with a cervix between 15 and 30 mm and a negative fibronectin test (<50 ng/mL; preterm birth rate, 2%) and 82 women with a cervix at >30 mm (preterm birth rate, 2%). Use of quantitative fibronectin alone resulted in a predicted risk of preterm birth within 7 days that ranged from 2% in the group with the lowest fibronectin level (<10 ng/mL) to 38% in the group with the highest fibronectin level (>500 ng/mL), with similar accuracy as that of the combination of cervical length and qualitative fibronectin. Combining cervical length and quantitative fibronectin resulted in the identification of an additional 19 women at low risk (preterm birth rate, 5%), using a threshold of 10 ng/mL in women with a cervix at <15 mm, and 6 women at high risk (preterm birth rate, 33%) using a threshold of >500 ng/mL in women with a cervix at >30 mm. CONCLUSION: In women with threatened preterm birth, quantitative fibronectin testing alone performs equal to the combination of cervical length and qualitative fibronectin. Possibly, the combination of quantitative fibronectin testing and cervical length increases this predictive capacity. Cost-effectiveness analysis and the availability of these tests in a local setting should determine the final choice.

Partial third nerve palsy and ocular neuromyotonia from displacement of posterior communicating artery detected by high-resolution MRI.

Ocular neuromyotonia is an unusual condition in which sustained, undesired contraction of one or more extraocular muscles occurs after normal muscle activation. Although most commonly reported after paraseller cranial irradiation for tumor, chronic nonaneurysmal vascular compression of the third nerve can produce partial ocular motor nerve paresis and ocular neuromyotonia. A 75-year-old woman presented with intermittent left-gaze-evoked binocular diplopia. She had an incomplete right third nerve palsy but became symptomatically diplopic and esotropic upon sustained left gaze. High-resolution brain magnetic resonance imaging showed displacement of the right posterior communicating artery and contact with the right third nerve. Gaze-evoked diplopia resolved with carbamazepine, but a partial third nerve paresis remained.

Fetal Growth Restriction Is Associated with Pregnancy Associated Plasma Protein A and Uterine Artery Doppler in First Trimester.

Fetal growth restriction (FGR) is a major cause of stillbirth and poor neurodevelopmental outcomes. The early prediction may be important to establish treatment options and improve neonatal outcomes. The aim of this study was to assess the association of parameters used in first-trimester screening, uterine artery Doppler pulsatility index and the development of FGR. In this retrospective cohort study, 1930 singleton pregnancies prenatally diagnosed with an estimated fetal weight under the third percentile were included. All women underwent first-trimester screening assessing maternal serum pregnancy-associated plasma protein A (PAPP-A), free beta-human chorionic gonadotrophin levels, fetal nuchal translucency and uterine artery Doppler pulsatility index (PI). We constructed a Receiver Operating Characteristics curve to calculate the sensitivity and specificity of early diagnosis of FGR. In pregnancies with FGR, PAPP-A was significantly lower, and uterine artery Doppler pulsatility index was significantly higher compared with the normal birth weight group (0.79 ± 0.38 vs. 1.15 ± 0.59, p < 0.001 and 1.82 ± 0.7 vs. 1.55 ± 0.47, p = 0.01). Multivariate logistic regression analyses demonstrated that PAPP-A levels and uterine artery Doppler pulsatility index were significantly associated with FGR (p = 0.009 and p = 0.01, respectively). To conclude, these two parameters can predict FGR < 3rd percentile.

Neutrophil Gelatinase-Associated Lipocalin and Hypertensive Disorders of Pregnancy: A Cohort Study in Twin Pregnancies.

Hypertensive disorders complicate more than 10% of twin pregnancies. Several studies showed increased neutrophil gelatinase-associated lipocalin (NGAL) values in women with singleton pregnancies and preeclampsia. This study aimed to assess NGAL values in twin pregnancies complicated by hypertensive disorders. We conducted a study of 242 consecutive twin pregnancies at the Medical University of Vienna. Serum NGAL was evaluated twice during pregnancy and once in the postpartum period. Furthermore, serum NGAL values were compared between women who developed hypertensive disorders and those who had normal blood pressure. In all twin pregnancies, mean NGAL values increased significantly from the first to the second visit (p = 0.004) and, further, after delivery (p < 0.001). NGAL was significantly higher in pregnancies that developed pregnancy hypertension or preeclampsia when compared to the control group at the first visit (109.2 ± 48.9 ng/mL vs. 91.9 ± 29.4 ng/mL, p = 0.04, respectively). The predictive power of first visit NGAL values for development of pregnancy hypertension or preeclampsia was evaluated. When using a cut-off value of 115 ng/mL, we obtained a sensitivity of 45% with a specificity of 77%. We conclude that women with twin pregnancies who develop hypertensive disorders of pregnancy showed increased NGAL values at 11−16 weeks.

Age-Dependency of Total Tau in the Cerebrospinal Fluid Is Corrected by Amyloid-ß 1-40: A Correlational Study in Healthy Adults.

BACKGROUND: Tau proteins are established biomarkers of neuroaxonal damage in a wide range of neurodegenerative conditions. Although measurement of total-Tau in the cerebrospinal fluid is widely used in research and clinical settings, the relationship between age and total-Tau in the cerebrospinal fluid is yet to be fully understood. While past studies reported a correlation between age and total-Tau in the cerebrospinal fluid of healthy adults, in clinical practice the same cut-off value is used independently of patient's age. OBJECTIVE: To further explore the relationship between age and total-Tau and to disentangle neurodegenerative from drainage-dependent effects. METHODS: We analyzed cerebrospinal fluid samples of 76 carefully selected cognitively healthy adults and included amyloid-ß 1-40 as a potential marker of drainage from the brain's interstitial system. RESULTS: We found a significant correlation of total-Tau and age, which was no longer present when correcting total-Tau for amyloid-ß 1-40 concentrations. These findings were replicated under varied inclusion criteria. CONCLUSION: Results call into question the association of age and total-Tau in the cerebrospinal fluid. Furthermore, they suggest diagnostic utility of amyloid-ß 1-40 as a possible proxy for drainage-mechanisms into the cerebrospinal fluid when interpreting biomarker concentrations for neurodegenerative diseases.

MR Pelvimetry for Breech Presentation at Term- Interobserver Reliability, Incidental Findings and Reference Values.

PURPOSE: Antepartal MR pelvimetry is used to assess the viability of vaginal breech delivery. We evaluated the reliability of MR pelvimetric measurements as well as incidental findings noted by different clinicians and assessed potential reference values. METHODS: In this monocentric study, the radiologic database was searched for obstetric MR pelvimetries with singleton breech pregnancies between 1999 and 2016. 99 consecutive MR pelvimetries were included. A structured, independent review was performed by six observers with three clinical experience levels (attending, fellow, junior resident from the departments of radiology and obstetrics). Image analysis entailed the quantitative assessment of conjugata vera (CV) and diameter transversalis (DT), image quality and incidental findings. Obstetric data was retrieved from the obstetric database for reference value assessment. RESULTS: Interobserver agreement was strong throughout (mean intraclass correlation coefficient range: 0.889 - 0.968). The individual measuring biases ranged between 0 - 2 mm, and the average limits of agreement were ±â€Š3 mm. Regarding the mode of delivery, the recommended cesarean section (rCS) group showed significantly smaller CV measurements (CV: 11.37 ±â€Š0.73, p-value < 0.0001) than any other delivery group. No statistical difference in CV between the vaginal delivery and unplanned cesarean section groups was found (p-value 0.902). DT measurements only showed a significant difference between rCS and elective cesarean section (p-value 0.039). 134 incidental findings were noted. CONCLUSION: Strong interobserver agreement irrespective of the reader's experience level supports MR pelvimetry as a reliable method for identifying women with fetopelvic disproportion in breech presentation. For a comprehensive appraisal of incidental findings, radiologic expertise is vital. KEY POINTS: · MR pelvimetry is a reliable method irrespective of the reader's experience level.. · Conjugata vera measurements aid in the prepartal viability assessment of vaginal breech delivery.. · Incidental findings are relatively common.. CITATION FORMAT: · von Bismarck A, Ertl-Wagner B, Stöcklein S et al. MR Pelvimetry for Breech Presentation at Term- Interobserver Reliability, Incidental Findings and Reference Values. Fortschr Röntgenstr 2019; 191: 424 - 432.

Neuro-ophthalmological presentation of giant intracavernous carotid artery aneurysm in a child.

An otherwise healthy, 11-year-old boy presented with a long-standing history of right eye esotropia associated with a right head turn. Following a mild blunt facial trauma, he was brought to an ophthalmologist for binocular horizontal diplopia. Cranial CT scan revealed a large, enhancing lesion in the right cavernous sinus. Neuro-ophthalmological evaluation showed abduction deficit of the right eye, right corneal anaesthesia, right upper lid ptosis and a smaller right pupil suggesting involvement of the intracavernous segments of the right abducens nerve, ophthalmic nerve and oculosympathetic fibres. Cerebral angiography confirmed a large aneurysm involving the petrous, lacerum and cavernous segments of the right internal carotid artery. The child underwent successful clipping of the aneurysm by the neurosurgery service.

Pre-transplant history of mental health concerns, non-adherence, and post-transplant outcomes in kidney transplant recipients.

OBJECTIVE: The association between pre-transplant mental health concerns and non-adherence and post-transplant outcomes after kidney transplantation is not fully established. We examined the relationship between a pre-transplant history of mental health concerns and non-adherence and post-transplant outcomes among kidney transplant recipients. METHODS: In this retrospective single center cohort study of adult kidney transplant recipients (n=955) the associations between the history of mental health concerns or non-adherence and the time from kidney transplant to biopsy proven acute rejection; death-censored graft failure and total graft failure were examined using Cox proportional hazards models. RESULTS: Mean (SD) age was 51 (13) years, 61% were male and 27% had a history of diabetes. Twenty-two and 11% of patients had mental health concerns and non-adherence, respectively. Fifteen percent of the patients had acute rejection, 5.6% had death-censored graft failure and 13.0% had total graft failure. The history of mental health concerns was not associated with acute rejection, death-censored graft failure or total graft failure. Patients with versus without a history of non-adherence tended to have higher cumulative incidence of acute rejection (23.3% [95% CI: 16.1, 33.2] vs. 13.6% [95% CI: 11.4, 16.2]) and death-censored graft failure (15.0% [95% CI: 6.9, 30.8] vs. 6.4% [95% CI: 4.7, 8.7]) (log rank p=0.052 and p=0.086, respectively). These trends were not significant after multivariable adjustment. CONCLUSION: In summary, a history of pre-transplant mental health concerns or non-adherence is not associated with adverse outcomes in patients who completed transplant workup and received a kidney transplant.

Development of the First Fluorescence Screening Assay for the SLC39A2 Zinc Transporter.

Zinc is an essential micronutrient that is crucial for many vital cellular functions such as DNA and protein synthesis, metabolism, and intracellular signaling. Therefore, the intracellular zinc concentration is tightly regulated by zinc transporters and zinc-binding proteins. The members of the SCL39 transporter family transport zinc into the cytosol. The SLC39A2 (hZIP2) protein is highly expressed in prostate epithelial cells and was found to be involved in prostate cancer development. Thus far, there is no specific modulator available for the SLC39 transporters. The aim of this study was to develop a screening assay for compound screening targeting hZIP2. Employing the pIRES2-DsRed Express 2 bicistronic vector, we detected human ZIP2 expression at the plasma membrane in transiently transfected HEK293 cells. Using the FLIPR Tetra fluorescence plate reader, we demonstrated that ZIP2 transports Cd(2+) with an apparent K(m) value of 53.96 nM at an extracellular pH of 6.5. The cadmium influx via hZIP2 was inhibited by zinc in a competitive manner. We found that hZIP2 activity can be measured using cadmium in the range of 0.1 to 10 µM with our assay. In summary, for the first time we developed an assay for human ZIP2 that can be adapted to other zinc transporters.

Human TRPV5 and TRPV6: key players in cadmium and zinc toxicity.

TRPV5 and TRPV6 are two major calcium transport pathways in the human body maintaining calcium homeostasis. TRPV5 is mainly expressed in the distal convoluted and connecting tubule where it is the major, regulated pathway for calcium reabsorption. TRPV6 serves as an important calcium entry pathway in the duodenum and the placenta. Previously, we showed that human TRPV6 (hTRPV6) transports several heavy metals. In this study we tested whether human TRPV5 (hTRPV5) also transports cadmium and zinc, and whether hTRPV5 together with hTRPV6 are involved in cadmium and zinc toxicity. The hTRPV5 mRNA and protein were expressed in HEK293 cells transiently transfected with pTagRFP-C1-hTRPV5. The overexpression of the hTRPV5 protein at the plasma membrane was revealed by cell surface biotinylation and immunofluorescence techniques. We observed that both cadmium and zinc permeate hTRPV5 in ion imaging experiments using Fura-2 or Newport Green DCF. Our results were further confirmed using whole-cell patch clamp technique. Transient overexpression of hTRPV5 or hTRPV6 sensitized cells to cadmium and zinc. Toxicity curves of cadmium and zinc were also shifted in hTRPV6 expressing HEK293 cells clones. Our results suggest that TRPV5 and TRPV6 are crucial gates controlling cadmium and zinc levels in the human body especially under low calcium dietary conditions, when these channels are maximally upregulated.

Stem cell therapy: a novel approach for vision restoration in retinitis pigmentosa.

Unfortunately, at present, degenerative retinal diseases such as retinitis pigmentosa remains untreatable. Patients with these conditions suffer progressive visual decline resulting from continuing loss of photoreceptor cells and outer nuclear layers. However, stem cell therapy is a promising approach to restore visual function in eyes with degenerative retinal diseases such as retinitis pigmentosa. Animal studies have established that pluripotent stem cells when placed in the mouse retinitis pigmentosa models have the potential not only to survive, but also to differentiate, organize into and function as photoreceptor cells. Furthermore, there is early evidence that these transplanted cells provide improved visual function. These groundbreaking studies provide proof of concept that stem cell therapy is a viable method of visual rehabilitation among eyes with retinitis pigmentosa. Further studies are required to optimize these techniques in human application. This review focuses on stem cell therapy as a new approach for vision restitution in retinitis pigmentosa.

Bilateral vision loss associated with radiofrequency exposure.

A 57-year-old otherwise healthy woman presented with painless binocular vision loss 1 week after direct application of radiofrequency energy to her orbits. She had no light perception bilaterally. Pupils were dilated and not reactive to light. Fundoscopic exam initially showed optic disc swelling in the right eye and a normal-appearing disc in the left eye. Magnetic resonance imaging of the brain and orbits showed gadolinium enhancement of both intraorbital optic nerves. She underwent a course of high-dose steroid treatment without recovery of vision. Optic discs were pale 11 weeks after injury. With exclusion of other possible causes, this represents a unique case of irreversible binocular optic nerve damage and blindness secondary to radiofrequency exposure.

Activation of the gene for the PDGF receptor beta1 (PDGFRbeta) in interleukin-3-dependent myeloid cells by retroviral insertional mutagenesis: implications for the transforming potential of PDGFRbeta.

Retroviral insertional mutagenesis has proven to be a powerful tool to identify genetic lesions disrupting normal hematopoiesis. The gene encoding the beta receptor for platelet-derived growth factor (PDGFRbeta) was identified as a target of retroviral mutagenesis in mutants selected for interleukin-3 (IL3)-independent growth. Expression of PDGFRbeta in the parental cells using a retroviral vector increased the frequency of factor-independent growth, confirming the significance of the retroviral integration site. Significantly, however, expression of the receptor did not induce IL3-independent growth in one step. In contrast, TEL-PDGFRbeta, the fusion protein generated by the t(5;12) translocation associated with chronic myelomonocytic leukemia, induced factor-independent growth in all transductants, demonstrating that the TEL-PDGFRbeta fusion protein is a more potent mitogenic signal. Nevertheless PDGFRbeta overexpression is sufficient to give a selective advantage to IL3-dependent cells under adverse conditions, allowing the selection of secondary mutations that impart IL3-independent growth. These results underline the power of insertional mutagenesis to identify subtle but initiating mutations that synergize with other lesions in oncogenic transformation.