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We report the case of a 4-month-old boy diagnosed with DiGeorge syndrome with novel ocular features. The patient was diagnosed through genetic testing, with a noted 22q11.2 deletion, and had the additional clinical findings of cardiac anomalies, Hirschsprung's disease, and intracranial microhemorrhages. Eye findings included bilateral microphthalmia, persistent fetal vasculature, chorioretinal coloboma, and a unilateral orbital cyst. Given no known additional inciting exposures, a dysgenic mechanism resulting in failed closure of developmental fissures associated with the chromosomal deletion likely gave rise to these combined pathologies.

To provide a comprehensive review of ocular and orbital manifestations of Erdheim-Chester Disease (ECD) and compare clinical outcomes with vemurafenib (INN) to historical treatments (HT). Primary outcomes are ophthalmic findings on presentation, changes in visual acuity, and mortality rate. Secondary outcomes include the progression of ocular findings, systemic involvements, and treatment modalities.All published literature from January 1983 to March 2021 was searched for ophthalmic manifestations of ECD. Clinical outcomes following HT were collected and compared with INN.Forty-seven patients with ECD and ophthalmic presentations were identified. The mean age was 49.6 years (SD = 15.0). Proptosis (65.6%) and extraocular muscle restrictions (42.5%) were the most common presenting signs. Of 41 (87.2%) patients with orbital masses on radiologic examination, 90.2% were bilateral, and 53.7% were located in the intraconal space. Ophthalmic examination was significant for xanthelasma (27.2%), optic disc edema (34.0%), and subretinal changes (21.3%). Common treatments were systemic steroids (76.6%), interferon-α (17.0%), and cyclophosphamide (14.9%). INN was less commonly used (12.8%). The mean change in logMAR visual acuity declined with HT (29.9%) but improved with INN (79.1%) (p 0.05). The proportion of eyes with complete vision loss increased after HT (p 0.05). The overall mortality rate was 27.7% and notably higher in the HT group (29.3%) when compared to the INN group (16.7%) (p 0.05).ECD presents with many ophthalmic manifestations. Although the intraocular treatments remain controversial, INN should be highly considered in treating orbital ECD patients with BRAF-V600E mutations to prevent and reverse vision loss.

BACKGROUND: Delayed treatment of congenital or infantile cataracts can cause deprivation amblyopia. Prompt diagnosis and surgical intervention is critical for optimal outcomes. This study assessed referral patterns for congenital or infantile cataracts in two regions of the United States. METHODS: The medical records of children 0-1 years of age with congenital or infantile cataracts at Stanford University (2008-2018) and Emory University (2010-2015) were reviewed retrospectively. RESULTS: A total of 111 children were included. Of these, 82 (74%) were initially evaluated by a primary care doctor, of whom 40 (49%) were referred directly to a pediatric cataract surgeon. Of 61 newborns 0-2 months of age, 9 (15%) were initially referred to an eye care provider before 6 weeks of age, but the initial evaluation by a pediatric cataract surgeon was delayed until after 6 weeks of age. Referral patterns were similar between the two institutions (P = 0.06). CONCLUSIONS: Many children with congenital of infantile cataracts are initially referred by a primary care doctor to an eye care provider who does not perform pediatric cataract surgery. Nevertheless, the majority of newborn infants with cataracts were evaluated by a pediatric cataract surgeon before 6 weeks of age.

Purpose To describe normative values for choroidal thickness in newborns and characterize their relationship to vitreoretinal features. Methods Term newborns underwent awake, handheld swept-source optical coherence tomography (SS-OCT) in this prospective cohort study. An automated segmentation algorithm followed by manual adjustments measured choroidal thickness at the fovea and five perifoveal locations. Two masked, trained graders, with a third mediating disagreements, analyzed scans for vitreoretinal findings. OCT vitreoretinal findings, including dome-shaped macula, subretinal fluid, punctate hyperreflective vitreous opacities, persistent inner retinal layers, foveal ellipsoid zone, tractional and non-tractional vitreous bands, epiretinal membrane, cystoid macular edema, vessel elevation, scalloped retinal layers, hyporeflective vessels, and retinal spaces, were assessed and correlated with foveal choroidal thickness using a generalized linear mixed model. Results Fifty-nine eyes of 39 infants (mean gestational age, 39.5 weeks; 18 male, 46%) were included. Mean foveal choroidal thickness was 455.5 ± 93.9 µm. Choroid was thinner inferonasally (343.6 ± 106.2 µm) compared to superonasally (368.4 ± 92.9 µm; P = 0.03) and superotemporally (369.6 ± 100.6 µm; P = 0.02). Thinner foveal choroidal thickness was associated with absence of a foveal ellipsoid zone (437.1 ± 78.5 µm vs. 553.7 ± 93.9 µm; P = 0.02). Choroidal thickness was not significantly associated with other OCT findings. Conclusions We identified an association between thinner choroid and foveal immaturity. Additional study is needed to determine whether choroidal development impacts visual outcomes. Translational Relevance Handheld SS-OCT achieved normative measurements for choroidal thickness across the macula in term newborns, providing a foundation for future investigations into the role of choroidal development in infancy.

Purpose: To describe a rare occurrence of acute vision loss and diffuse alveolar hemorrhage following a treatment of injectable gluteal cosmetic filler. Patient and methods: A 20-year-old female underwent a cosmetic injection of unknown components for gluteal augmentation. Within hours she developed progressive shortness of breath secondary to diffuse alveolar hemorrhage. She presented to ophthalmology 6 weeks later with a history of bilateral decreased vision. Clinical examination revealed cotton wool spots and retinal hemorrhages. Fluorescein angiography demonstrated macular vascular pruning and an enlarged foveal avascular zone. Results: The patient was observed and vision did not improve after 8 months of follow-up. Conclusion: These findings were attributed to a Purtscher-like retinopathy secondary to systemic inflammation induced by the filler and/or direct microembolization of the injected material or fat. To the best of the authors’ knowledge, this is the first documented case of diffuse alveolar hemorrhage and ischemic bilateral vision loss in a patient undergoing gluteal augmentation with dermal filler.

Central disruption of fusion refers to a subject's inability to fuse images, resulting in constant diplopia. Severely reduced vergences, or vergence anomalies, producing markedly decreased fusional amplitudes resembling fusional disruption have not been reported previously with convergence insufficiency. We report 3 patients with severe vergence anomalies in the setting of convergence insufficiency.

Cohen syndrome is a rare disease that causes myopia and retinal degeneration in the setting of developmental delay and characteristic craniofacial features. We report optical coherence tomography (OCT) abnormalities in 4 patients with Cohen syndrome, 2 of whom have longitudinal follow-up. All subjects had schisis-like changes, with cystoid spaces in the inner retina as well as diffuse outer retinal atrophy sparing the subfoveal region. Ophthalmologic findings in 1 patient led to the work-up that resulted in a diagnosis of Cohen syndrome, suggesting that characteristic retinal abnormalities visualized by fundus examination and OCT may represent distinguishing features of this syndrome.

Purpose: We report a patient with severe multi-organ dysfunction of unknown origin who presented with bilateral orbital and chorioretinal manifestations that led to the diagnosis of Erdheim-Chester Disease (ECD). Observations: ECD is a rare, histiocytic, proliferative disorder characterized by multi-systemic organ involvement that has historically lacked effective therapy. Our patient underwent genetic testing that was positive for the BRAF V600E mutation; therefore, the patient was treated with vemurafenib. Conclusions and importance: This case demonstrates the rare orbital and intraocular manifestations of ECD and the unfortunate impact of a delayed diagnosis, the importance of early gene therapy testing for management decisions, and the utilization of targeted directed therapy to improve visual outcomes and quality of life. Keywords: Histiocytosis, Vemurafenib, Orbital, Chorioretinal, Xanthomatous, Lipogranulomatous, BRAF

Purpose To report the clinical features, antibiotic susceptibility profiles, treatment, and visual acuity (VA) outcomes of endophthalmitis caused by Corynebacterium species. Design Retrospective case series. Participants Patients with endophthalmitis caused by Corynebacterium species. Methods Microbiology database records were retrospectively reviewed for all patients with endophthalmitis caused by Corynebacterium species from January 1, 1990, to December 31, 2012, at a large university referral center. The corresponding clinical records were then reviewed to evaluate endophthalmitis clinical features and treatment outcomes. Main Outcome Measures Presenting clinical features, visual acuity outcomes, and antibiotic susceptibility patterns. Results For the 10 patients identified, clinical settings included post–cataract surgery (n = 6), post–penetrating keratoplasty (n = 2), and posttrabeculectomy (n = 2). The mean time from surgical procedure to presentation with endophthalmitis was 6.8 months (range: 1 day to 28 months). All isolates were susceptible to vancomycin. Presenting VA ranged from 7/200 to no light perception. Initial treatment strategies were vitreous tap and intravitreal antibiotic injection (n = 5) and pars plana vitrectomy with intravitreal antibiotic injection (n = 5). VA outcomes were ≥20/60 in 5 of 10 patients (50%) and ≤20/400 in 5 of 10 patients (50%). Conclusions The most common clinical setting was post–cataract surgery. All isolates were susceptible to vancomycin. Despite prompt treatment with appropriate antibiotics, visual outcomes varied.

To report the clinical settings, bacterial isolates, antibiotic sensitivities, and visual acuity outcomes of patients with persistently positive vitreous cultures after intravitreal antibiotics.Consecutive, noncomparative case series.setting: Tertiary care center.Thirty-six eyes of 36 patients with exogenous endophthalmitis with the same bacterial organism identified on at least 2 consecutive vitreous cultures from 1981 to 2015.Vitreous cultures with intravitreal injections of antibiotics and pars plana vitrectomies with intravitreal antibiotics.Bacterial isolates, antibiotic sensitivities, visual outcomes.Thirty-six eyes of 36 patients met the study criteria. The mean follow-up was 26.5 months. The most common clinical settings were after cataract extraction (18/36, 50%) and glaucoma surgery (11/36, 31%). The mean initial visual acuity was 2.16 ± 0.77 logMAR (Snellen equivalent ≈20/2900), and there was no statistically significant change at the final evaluation (2.08 ± 0.97 logMAR, ≈20/1900, P = .72). The most common bacteria were Staphylococcus (11/36, 31%) and Streptococcus (9/36, 25%). Gram-positive bacteria were sensitive to vancomycin (27/27, 100%); gram-negative bacteria were sensitive to amikacin (5/5, 100%). The antibiotic sensitivities were the same on repeat cultures in 34 of 36 patients (94%). The initial treatment was a vitreous culture and intravitreal injection of antibiotics in 28 of 36 patients (78%). The vision at the last follow-up was 20/200 or better in 12 patients (33%) and no light perception in 11 of 36 patients (31%).The most commonly identified organisms were gram-positive bacteria. There was good concordance in the antibiotic sensitivities between initial and subsequent cultures. Patients with persistently vitreous culture-positive endophthalmitis had poor visual outcomes.

To report the clinical features, antibiotic susceptibility profiles, treatment, and visual acuity (VA) outcomes of endophthalmitis caused byRetrospective case series.Patients with endophthalmitis caused byMicrobiology database records were retrospectively reviewed for all patients with endophthalmitis caused bypresenting clinical features, visual acuity outcomes, and antibiotic susceptibility patterns.Of 10 patients identified, clinical settings included post-cataract surgery (n = 6), post-penetrating keratoplasty (n = 2), and post-trabeculectomy (n = 2). The mean time from surgical procedure to presentation with endophthalmitis was 6.8 months (range: 1 day to 28 months). All isolates were vancomycin susceptible. Presenting VA ranged from 7/200 to no light perception. Initial treatment strategies were vitreous tap and intravitreal antibiotic injection (n = 5) and pars plana vitrectomy with intravitreal antibiotic injection (n = 5). VA outcomes were ≥ 20/60 in 5 (50%) of 10 patients and ≤ 20/400 in 5 (50%) of 10 patients.The most common clinical setting was post-cataract surgery. All isolates were susceptible to vancomycin. Despite prompt treatment with appropriate antibiotics, there were variable visual outcomes.

Background The aims of this study were to evaluate visual function outcomes in idiopathic intracranial hypertension (IIH) patients who underwent ventriculoperitoneal (VP) shunt for visual loss and to determine a VP shunt survival curve over time. Methods A retrospective medical record review was performed of all new IIH patients first evaluated at our institution who underwent VP shunt placement over a 7-year period (2004-2010). There were 2 primary outcome measures: the first being visual acuity (VA) and the second being shunt survival. Patients who received VP shunt for visual loss were included in the visual outcome analysis, and all patients who received VP shunt for any reason were included in the shunt survival analysis. Results Of the 338 new patients with IIH, 19 patients (6%) met the inclusion criteria and 17 underwent VP shunt for visual loss and 2 for headaches. Average follow-up was 21.2 months (range, 5-1,342 days). Of the 17 patients who had VP shunt for visual loss, 5 patients had optic nerve sheath fenestration (ONSF) surgery before VP shunt, and 1 patient had bilateral ONSF surgery after VP shunt. Median VA before shunt was 20/200 in the worse eye (range, 20/20 to NLP) and 20/40 in the better eye (20/20 to HM). Median VA after shunt was 20/60 in the worse eye (20/20 to lumboperitoneal) and 20/30 in the better eye (20/20 to 20/800). The improvement in VA was statistically significant in both worse eyes (P = 0.002, Wilcoxon signed-rank test) and better eyes (P = 0.028). The mean automated visual field (AVF) mean deviation (MD) of available AVFs before shunt was 223.36 dB (range, 233.38 to 27.01 dB) for the worse eye (n = 11) and 219.66 dB (230.11 to 25.91 dB) for the better eye (n = 11). Mean AVF MD deviation of available AVFs after shunt was 220.68 dB (232.13 to 23.97 dB) for the worse eye (n = 11) and 216.35 dB (232.13 to 21.00 dB) for the better eye (n = 11): this improvement was not significant (P = 0.27, P = 0.26, respectively). Independent masked record reviews by 3 neuro-ophthalmologists showed that 9 (53%) patients improved, 5 (29%) unchanged, 1 (6%) worsened, and 2 (12%) were indeterminate. Kaplan-Meier analysis showed a persistent steady decrease of functioning VP shunts over the entire period of 36 months with 80%, 65%, and 48% of VP shunts functioning without replacement, removal, or revision at 12, 24, and 36 months, respectively. Conclusion VP shunts improve or stabilize most IIH patients presenting with severe progressive visual loss or those with visual loss refractive to medical treatment and ONSF. Survival analysis shows persistent decrease of functioning shunts over time.

OBJECTIVE To describe utilization trends of an ophthalmology-specific emergency department (ED). METHODS Prospective cohort study of new patients presenting in the ophthalmology ED for at least a 30-day period in the spring of each year for five consecutive years (2010-14) at a university referral center. A data form, including information about the ED visit and patient demographics, was included in each patient chart. Data were analyzed with Pearson chi-square test and multiple logistic regression. RESULTS A total of 5323 chart data forms were completed. An average of 42.2 new patients per day presented to the ophthalmology ED. Most common diagnoses were viral conjunctivitis (8.7%), dry eye syndrome (6.6%), and corneal abrasion (6.6%). Non-emergent visits accounted for 35.8% of surveys completed. Factors associated with non-emergent visits included female gender, age 65 years or older, weekday visits, and patient symptom duration greater than one week (p < 0.0001 for each factor). When compared to all other insurance categories combined, patients who were members of the regional public assistance program were the most likely to present with a non-emergency (48.5% versus 34.9%, p < 0.001), while Workers' Compensation patients were least likely to present with a non-emergency (16% versus 36.5%, p < 0.001). CONCLUSIONS Over one-third of new patient visits were non-emergent. Factors predictive of non-emergent patient visits were female gender, age 65 years or older, duration of symptoms greater than one week, weekday visits, and the form of insurance coverage.

Purpose To develop an automated method of localizing and discerning multiple types of findings in retinal images using a limited set of training data without hard-coded feature extraction as a step toward generalizing these methods to rare disease detection in which a limited number of training data are available. Methods Two ophthalmologists verified 243 retinal images, labeling important subsections of the image to generate 1324 image patches containing either hemorrhages, microaneurysms, exudates, retinal neovascularization, or normal-appearing structures from the Kaggle dataset. These image patches were used to train one standard convolutional neural network to predict the presence of these five classes. A sliding window method was used to generate probability maps across the entire image. Results The method was validated on the eOphta dataset of 148 whole retinal images for microaneurysms and 47 for exudates. A pixel-wise classification of the area under the curve of the receiver operating characteristic of 0.94 and 0.95, as well as a lesion-wise area under the precision recall curve of 0.86 and 0.64, was achieved for microaneurysms and exudates, respectively. Conclusions Regionally trained convolutional neural networks can generate lesion-specific probability maps able to detect and distinguish between subtle pathologic lesions with only a few hundred training examples per lesion.

Awoman in her 30s presentedwith a 3-month history of bilateral blurry vision with transient visual obscurations and a 1-month history of tinnitus. Funduscopic examination findings were concerning for bilateral optic disc edema, which was worse in the right eye compared with the left (Figure 1). Magnetic resonance imaging of thebraindemonstratedmultiple cysts in theposterior fossa, including a large cyst inducing obstructive hydrocephalus at the level of the fourthventriclemeasuring1.2cm × 1.6cminanteroposteriorand transverse dimensions (Figure 2). She underwent emergent suboccipital craniotomy with removal of the cysts and placement of a temporary external ventricular catheter. Cerebrospinal fluid analysis results revealed no protein, white blood cells, or organisms. Surgical pathology confirmed the diagnosis of neurocysticercosis. The patient was treated for 14 days with 400mg twice daily of albendazole by mouth along with intravenous dexamethasone, 2 mg, twice daily followed by a rapid oral corticosteroid taper. Follow-up cerebrospinal fluid analysis results revealed rare white blood cells, no protein, and no organisms. Twomonths later, the patient presentedwith continued blurry vision and bilateral sixth nerve palsies and required ventriculoperitoneal shunt placement owing to a communicating hydrocephalus. At follow-up, the patient had resolution of all visual symptoms. Follow-up magnetic resonance imaging demonstrated reduction in size of the culprit cyst to 0.5 cm × 0.8 cm in anteroposterior and transverse dimensions.

Floaters most commonly occur in the middle age due to age-related changes in vitreous structure and light scattering by the posterior vitreous cortex after collapse of the vitreous body during posterior vitreous detachment (PVD). In youth, floaters are most often due to myopic vitreopathy. Vitreous floaters can have a negative impact on visual function and in turn the quality of life. Techniques to characterize floaters clinically include ultrasound imaging, optical coherence tomography, and dynamic light scattering for structural characterization. Functional impact can be assessed by straylight measurements, as well as contrast sensitivity testing. When the severity of floater symptomatology is significant, commonly used therapies include neodymium:yttrium-aluminum-garnet (YAG) laser and limited 25-gauge vitrectomy. While the former is of unproven efficacy, the latter has been shown to be a safe, effective, and definitive cure that improves patients’ quality of life and eradicates symptomatology produced by light scattering and diffraction. It is thus reasonable to offer limited vitrectomy to individuals who have attempted to cope unsuccessfully and in whom functional deficit can be objectively demonstrated by testing contrast sensitivity, an important aspect of vision.

Floaters impact vision but the mechanism is unknown. We hypothesize that floaters reduce contrast sensitivity function, which can be normalized by vitrectomy, and that minimally invasive vitrectomy will have lower incidences of retinal tears (reported at 30%) and cataracts (50-76%).Seventy-six eyes (34 phakic) with floaters were evaluated in 2 separate studies. Floater etiologies were primarily posterior vitreous detachment in 61 of 76 eyes (80%) and myopic vitreopathy in 24 of 76 eyes (32%). Minimally invasive 25G vitrectomy was performed without posterior vitreous detachment induction, leaving anterior vitreous, and using nonhollow probes for cannula extraction. Efficacy was studied prospectively (up to 9 months) in 16 floater cases with Freiburg Acuity Contrast Testing (Weber index [%W] reproducibility = 92.1%) and the National Eye Institute Visual Function Questionnaire. Safety was separately evaluated in 60 other cases followed up on an average of 17.5 months (range, 3-51 months).Floater eyes had 67% contrast sensitivity function attenuation (4.0 ± 2.3 %W; control subjects = 2.4 ± 0.9 %W, P0.013). After vitrectomy, contrast sensitivity function normalized in each case at 1 week (2.0 ± 1.4 %W, P0.01) and remained normal at 1 month (2.0 ± 1.0 %W, P0.003) and 3 months to 9 months (2.2 ± 1.5 %W, P0.018). Visual Function Questionnaire was 28.3% lower in floater patients (73.2 ± 15.6, N = 16) than in age-matched control subjects (93.9 ± 8.0, N = 12, P0.001), and postoperatively improved by 29.2% (P0.001). In the safety study of 60 floater cases treated with vitrectomy, none developed retinal breaks, infection, or glaucoma after a mean follow-up of 17.5 months. Only 8 of 34 cases (23.5%) required cataract surgery (none younger than 53 years) at an average of 15 months postvitrectomy.Floaters lower contrast sensitivity function, which normalizes after vitrectomy. Visual Function Questionnaire quantified improvement in satisfaction. Not inducing posterior vitreous detachment reduced retinal tear incidence from 30% to 0% (P0.007). Postvitrectomy cataract incidence was reduced from 50% to 23.5% (P0.02). This approach thus seems effective and safe in alleviating the visual dysfunction induced by floaters.

We report here the in vivo conversion of [3H]myoinositol to [3H]chiroinositol. After labeling intraperitoneally with [3H]myoinositol for 3 days to reach radioisotope equilibrium in urine, [3H]chiroinositol was isolated from tissues and purified after 6 N HCl hydrolysis by two sequential paper chromatographies and high performance liquid chromatography (HPLC). Percent conversion of [3H]myoinositol to [3H]chiroinositol was highest in urine (36%), liver (8.8%), muscle (8.8%), and blood (7.6%) with intestine, brain, kidney, spleen, and heart decreasing in percentage from 2.8 to 0.7%. Labeling of other inositol isomers including scyllo-, neo-, and epi-, and mucoinositol was minimal, approximately 0.06% of [3H]myoinositol. Glucose was unlabeled, but glucuronate, the product of myoinositol oxidation, was labeled up to 1.5% of the [3H] myoinositol. Acid hydrolysates of combined inositol-containing phospholipids contain significant labeled chiroinositol. [3H]Phosphatidylinositols and [3H]glycosylphosphatidylinositols were extracted from liver, muscle, and blood, isolated by thin layer chromatography, and inositols purified by HPLC after acid hydrolysis. Percent conversion of [3H]myoinositol to [3H] chiroinositol was highest in blood (60.4%) followed by muscle (7.7%) and liver (2.2%).

To test the hypothesis that insulin mediators serve as the signal transduction system for insulin's steroidogenic actions in human placental cytotrophoblasts, we examined the effects of two inositolglycan insulin mediators, the insulin pH 2.0 chiro-inositol mediator (IM-pH 2.0) and the insulin pH 1.3 myo-inositol mediator (IM-pH 1.3), on cytotrophoblastic steroidogenesis. When human cytotrophoblasts were incubated in medium supplemented with androstenedione for 24 h, treatment with IM-pH 2.0 or IM-pH 1.3 suppressed aromatase activity by 15% (P less than 0.05) and 49% (P less than 0.05), respectively, compared to insulin, which suppressed aromatase activity by 21% (P less than 0.05). When cytotrophoblasts were incubated in medium supplemented with pregnenolone for 24 h, treatment with IM-pH 2.0 or IM-pH 1.3 stimulated 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) activity by 145% (P less than 0.05) and 168% (P less than 0.05), respectively, compared to insulin, which stimulated 3 beta HSD activity by 63% (P less than 0.05). Suppression of aromatase activity and stimulation of 3 beta HSD activity by inositolglycan mediators were both concentration dependent. Moreover, preincubation of cytotrophoblasts with the antiinositolglycan antibody alpha IGP completely abolished insulin's ability to either inhibit aromatase or stimulate 3 beta HSD activity. These results indicate that insulin mediators mimic insulin's effects on cytotrophoblastic aromatase and 3 beta HSD activities and suggest that inositolglycan mediators are the signal transduction mechanism responsible for insulin's regulation of human placental steroid hormone biosynthesis.

We isolated from beef liver a putative insulin mediator termed INS-2, 1. Its structure was determined to be a novel inositol glycan pseudo-disaccharide Mn(2+) chelate containing D-chiro-inositol 2a (as pinitol) and galactosamine. Purification methods were scaled up from those previously reported to isolate an inositol glycan with similar composition from rat liver.(1) Structure of the beef liver glycan was determined by degradative chemistry and 2D NMR spectroscopy and confirmed by chemical synthesis. Its structure is 4-O-(2-amino-2-deoxy-beta-D-galactopyranosyl)-3-O-methyl-D-chiro-inositol 1 (INS-2, Figure 1). Its role as an insulin mimetic was demonstrated by its action in vivo to decrease elevated blood glucose injected to low-dose streptozotocin diabetic rats in a stereospecific and dose-dependent manner. The pseudo-disaccharide also stimulated [(14)C]glucose incorporation into [(14)C]glycogen in a dose-dependent manner in H4IIE hepatoma cells in the presence of insulin, thus enhancing insulin action. Only when chelated to Mn(2+) did it activate pyruvate dehydrogenase phosphatase in vitro in a dose-dependent manner. To our knowledge, this is the first example of a beta-1,4-linked inositol glycan consisting of D-chiro-inositol and galactosamine isolated from animal tissues with insulin mimetic actions.

Two inositol phosphoglycans (IPG) isolated from beef liver and designated as putative insulin mediators were demonstrated to reciprocally enhance the dephosphorylation of inhibitor-1 (INH-1) and DARPP-32, thus directly activating phosphatase 2C and disinhibiting phosphatase 1 in a potential protein phosphatase 2C --phosphatase 1 cascade mechanism. One IPG termed pH 2.0, containing Dchiro-inositol and galactosamine, stimulated the dephosphorylation of INH-1 and DARPP-32 in a dose-dependent manner in the low micromolar range. A second, termed pH 1.3, containing myo-inositol glucosamine and mannose acted reciprocally to inhibit the cAMP-dependent protein kinase phosphorylation of INH-1 and DARPP-32 in a dose-dependent manner in the low micromolar range. These model experiments are discussed in terms of the observed dephosphorylation of INH-1 with insulin action documented in the literature and the activation of both phosphatase 1 and 2C described in intact cells and in vivo with insulin action.

We compared the effects of infusing a chemically defined chiro-inositol glycan putative insulin mediator with an equivalent dose of insulin in low-dose (45 mg/kg) streptozotocin diabetic rats. Insulin decreased plasma glucose levels from 17.32 +/- 0.17 to 3.96 +/- 0.064 mmol/l (p < 0.0002) in 120 min, a decrease of 77.13%, while the putative mediator promoted a decrease in plasma glucose from 14.85 +/- 0.084 to 7.22 +/- 0.13 mmol/l (p < 0.007) in 60 min. The putative mediator maintained euglycaemia over the ensuing 60 min with a plasma glucose level of 7.01 +/- 0.10 mmol/l at 120 min. Thus, insulin further reduced the plasma glucose from euglycaemia at 60 min to produce hypoglycaemia at 120 min. The lack of production of hypoglycaemia by the putative mediator can be explained by its inhibition of glucose-stimulated insulin secretion by the islet beta cells, thus providing a potential negative feedback regulatory mechanism; or by its selective action on muscle to increase glycogen synthesis. The significance of these results in terms of future directions in drug design is herein considered.

Two insulin mediators, inositol phosphoglycans, were isolated from bovine liver by methods previously developed for rat liver, i.e. chromatography on an AG 1 x 8 ion exchange column and selective elution with HCl at pH 2.0 and 1.3. The pH 2.0 mediator containing D-chiroinositol stimulated pyruvate dehydrogenase phosphatase, whereas the pH 1.3 mediator containing myo-inositol inhibited cAMP-dependent protein kinase. Each mediator was further purified by thin layer and Bio-Gel P4 column chromatography and injected ip into normal fed rats together with [U-14C]glucose. After 2.5 h, diaphragms were removed, and glycogen isolated. Insulin mediators, like insulin, stimulated [U-14C]glucose incorporation into glycogen by 150-160% in a dose-dependent manner in the nanomolar range. Mediators injected iv in the nanomolar range into low dose streptozotocin-diabetic rats decreased plasma glucose 30-45% in 30-60 min, with a return to basal concentrations after 150-180 min. These in vivo insulin-like effects of mediator were observed without changes in serum insulin concentrations. The pH 2.0 mediator was 50-100 times more active (per nmol organic phosphate) than the pH 1.3 mediator in the ip diaphragm glycogenesis assay. Mediator effects on diaphragm were completely blocked by preincubation with an immunopurified inositol phosphoglycan antibody. Both mediators were equally active iv in lowering plasma glucose (per nmol inositol) at concentrations comparable to those of insulin.

A two stage assay for detecting insulin mediator based upon its stimulation of soluble pyruvate dehydrogenase (PDH) phosphatase to activate soluble pyruvate dehydrogenase complex (PDC) has been developed. This coupled assay determines the activation of PDC by monitoring production of [14C]CO2 from [1-14C]pyruvic acid. In addition to being more sensitive than the rat liver mitoplast assay previously used, it allows for the separation and investigation of the effects of mediator on the PDH phosphatases individually. It has been previously shown that the insulin mediator stimulates the most abundant PDH phosphatase, the divalent cation dependent PDH phosphatase, by decreasing the phosphatase's metal requirement (1). A metal independent PDH phosphatase has been found in bovine heart mitochondria. This phosphatase is not immunoprecipitated by antiphosphatase 2A antibody, it is not inhibited by okadaic acid, and it is not stimulated by spermine. However, it is stimulated (more than threefold) by insulin mediator prepared from isolated rat liver membranes. It is inhibited by Mg-ATP, with half-maximal inhibition at 0.3 m m ; however, this inhibition is overcome by the insulin mediator.

We have studied the mechanism of generation of insulin mediators by using specific antibodies raised against the oligosaccharide anchor of membrane proteins. These antibodies (i) block the in vitro effects of purified insulin mediators and (ii) block the insulin-induced stimulation of pyruvate dehydrogenase in intact BC3H1 myocytes but not insulin-stimulated glucose uptake, generation of diacylglycerol, or generation of insulin mediators. When added to intact cells in the presence of insulin, these antibodies induce the accumulation of insulin mediator activity in the extracellular medium. We therefore conclude that these anti-inositolglycan antibodies block some of the effects of insulin by inhibiting the uptake of specific insulin mediators generated outside the cell.

It has been proposed that the active centre of cyclic AMP-dependent protein kinase contains an arginine-recognition site, which is considered to be essential for the function of the catalytic subunit of the kinase [Matsuo, Huang & Huang (1978) Biochem. J.173, 441–447]. The catalytic subunit can be inactivated by 3-(3-dimethylaminopropyl)-1-ethylcarbodi-imide and glycine ethyl ester at pH6.5. The enzyme can be protected from inactivation by preincubation with histone, a protein substrate of the enzyme. On the other hand, ATP, which also serves as a protein kinase substrate, does not afford protection. Polyarginine, a competitive inhibitor of protein kinase, which is known from kinetic studies to interact specifically with the arginine-recognition site, partially protects the catalytic subunit from inactivation by 3-(3-dimethylaminopropyl)-1-ethylcarbodi-imide. These results lead to the conclusion that the site of modification by carbodi-imide/glycine ethyl ester is most likely located at the arginine-recognition site of the active centre. A value of 1.7±0.2 (mean±s.d.) mol of carboxy groups per mol of catalytic subunit has been obtained for the number of essential carboxy groups for the function of protein kinase; a complete chemical modification of these essential carboxy groups results in total loss of catalytic activity. Finally, we have identified the essential carboxy group in the catalytic subunit of cyclic AMP-dependent protein kinase as being derived from glutamate residues. This is achieved by a three-step procedure involving an extensive proteolytic digestion of the [1-14C]glycine ethyl ester-modified enzyme and two successive high-voltage electrophoreses of the hydrolysate. It is concluded that 1.7mol of glutamyl carboxy groups per mol of catalytic subunit may be considered a component of the arginine-recognition site in the active centre of cyclic AMP-dependent protein kinase.

The naturally-occurring polyamines were found to stimulate glycogen synthase phosphatase from rat skeletal muscles. The sequence of effectiveness in the stimulation was spermine greater than spermidine greater than putrescine. It was shown that the spermine-sensitive phosphatase was present primarily in the soluble fraction of the muscle extract. In the presence of spermine, the phosphatase activity can be further stimulated by Mn2+; however, a lower Mn2+ concentration is required for the activation of the enzyme in comparison with that in the absence of spermine. Kinetic studies indicated that activation of glycogen synthase phosphatase by spermine was achieved by an increase in its V without significant alteration in the Km, suggesting that spermine directly stimulated the catalytic efficiencly of the phosphatase enzyme.

Substantial evidence suggests that insulin receptor-associated protein kinase may play a pivotal role in the expression of the intracellular effects of insulin. This study was undertaken to determine whether insulin receptor kinase contributes to the generation of putative insulin mediators. The effect of ATP and divalent cation addition on the production of insulin mediators from liver plasma membranes was investigated. ATP (1 mM) added to liver plasma membranes in the absence of divalent cations enhanced insulin-stimulated release/generation of mediator slightly (approximately 3-fold). ATP in the presence of Mn2+ further increased release/generation of mediator markedly (approximately 100-fold). In contrast, ATP in the presence of Mg2+ had no stimulatory effect. Mn2+ and Mg2+ alone were ineffective. Addition of EDTA completely diminished the stimulatory effects of insulin, ATP, and Mn2+. The stimulation was ATP-specific since other nucleotides and nonhydrolyzable analogues of ATP had no or very weak activity. ATP-Mn2+ stimulated insulin-dependent mediator release/generation in a dose-dependent manner. These results suggest that insulin mediator release/generation is markedly stimulated by an ATP-Mn2+-dependent phosphorylation reaction, similar to insulin-stimulated receptor tyrosine kinase phosphorylation.

A novel putative mediator of insulin action which acts to inhibit adenylate cyclase and cAMP-dependent protein kinase has been purified from livers of insulin-treated streptozotocin-diabetic rats. It was increased by short term (5-min) insulin injections in vivo and purified several thousand-fold by Sephadex and HPLC. Its mol wt was somewhat larger (2500) than previous mediators identified, and it was more hydrophobic in character. Its mechanism of action or adenylate cyclase was determined and found to be chiefly directed against the catalytic subunit. Its action on the cAMP-dependent protein kinase was found to be competitive with regard to protein substrate, but noncompetitive with regard to ATP and cAMP. Its relationship to other putative insulin mediators and the mechanism of insulin action is discussed.

The exchange rate of unlabeled adenosine 3',5'-monophosphate (cAMP) with labeled [3H]cAMP in the dimeric regulatory subunit-cAMP complex of cAMP-dependent protein kinase, type I, purified from rabbit skeletal muscle is described by using the equilibrium isotope exchange technique. Results indicate that the rate of exchange carried out in the absence of the catalytic subunit (C) is rather slow with a half-life of approximately 870 s. This slow exchange rate is not affected by the presence of MgATP (50 microM). However, when both MgATP (50 microM) and C (1-13 NM) are present, the rate of isotope exchange is observed to increase markedly. Furthermore, less than stoichiometric amounts of C are required for the increase in the rate of cAMP exchange, indicating that the effect of C on the rate enhancement is a catalytic process. These results indicate that in the presence of MgATP, a ternary complex between C and regulatory subunit-cAMP complex must be formed, and a dynamic equilibrium between the eternary complex and its dissociable species must be reached within seconds. On the basis of our kinetic data, it is proposed that the formation of this ternary complex intermediate allows the rapid activation or the inactivation of cAMP-dependent protein kinase following changes in the cellular cAMP levels.

The My-1 cell surface antigen is expressed on human granulocytes and granulocytic precursor cells. The sugar sequence which occurs in the glycolipid, lacto-N-fucopentaose III ceramide, in several higher glycolipids, and in glycoproteins, contains the epitope recognized by anti-My-1 and 17 other monoclonal antibodies with the same cellular specificity. Download : Download high-res image (12KB) Download : Download full-size image

Two fractions of protein kinase(s) from rabbit skeletal muscle have been shown to catalyze the phosphorylation of endogenous protein, histone, and glycogen synthase I utilizing UTP, GTP, CTP, and ITP as phosphoryl donors. With one protein kinase fraction, it was found that the enzymatic activity was enhanced by Mn2+ when CTP served as the phosphoryl donor. This is in contrast to the inhibitory effect of Mn2+ on the kinase activity with ATP as the phosphoryl donor. With the second protein kinase fraction, the UTP, GTP, CTP and ITP associated phosphorylation reactions were found to be inhibited by cyclic AMP, whereas the phosphorylation reaction in which ATP served as the phosphoryl donor was found to be stimulated by cyclic AMP. These results suggest that different forms of the protein kinase(s) may exist which have different nucleoside triphosphate donor specificity and metal ion requirement. The serine residues of endogenous protein have been demonstrated to be the sites of phosphorylation when UTP, GTP, CTP and ITP served as the phosphoryl donors.

We have previously shown that in rat H4 hepatoma cells insulin enhances the nuclear transcription of p33 mRNA in a dose- and time-dependent manner, with no alteration in mRNA half-time (t1/2). Presumably, this effect is mediated by the cell surface receptor. In this report, we have investigated the effect of putative insulin mediator fractions which act to control metabolic events on p33 mRNA accumulation in these cells. Initial experiments originally demonstrated an insulin-like effect of an added putative metabolic fraction to enhance p33 mRNA concentrations. However, when the fetal calf serum supply was changed, the effect of insulin remained, but that of added mediator was no longer observed. After a series of experimental approaches designed to alter the permeability of the cell membrane, it was found that in the presence of increased Ca2+, the effect of mediator could again be observed. The present data demonstrate that the partially purified cAMP-dependent protein kinase/adenylate cyclase inhibitory putative mediator fractions from liver and muscle enhance p33 mRNA accumulation in intact H4 hepatoma cells by a mechanism that is differentiated from that of insulin. The action of the putative mediator is inhibited by cycloheximide, while the action of insulin itself is not. These results suggest that insulin may control nuclear transcription by multiple signaling mechanisms. Alternatively, the added putative metabolic mediator may not enter the cell in the presence of cycloheximide or is inactive as such within the cell and must first be converted to an active species by a step requiring protein synthesis.

1. 1. The regulatory subunit of Type I cAMP-dependent protein kinase from rabbit skeletal muscle can bind [ 3 H]cAMP to form the R-[ 3 H]cAMP complex, and the slow phase of the enhanced exchange of free cAMP with [ 3 H]cAMP from the R-[ 3 H]cAMP complexes was studied under various conditions using the equilibrium isotope exchange technique. 2. 2. Results indicate that Mg-ATP and the catalytic subunit are absolutely required for the enhanced exchange reaction to occur, but phosphorylation of the regulatory subunit by Mg-ATP does not play a determining role in the slow rate of the dissociation/association of the Type I protein-kinase in the presence of cAMP and the catalytic subunit. 3. 3. We interpret the role of Mg-ATP as being one in which it may provide the structural attributes required for formation of a stabilized transient state of the cAMP-regulatory subunit-catalytic subunit ternary complex, an obligatory intermediate involved in the dissociation/association of Type I cAMP-dependent protein kinase.

Deproteinized skeletal muscle extracts free of major nucleotides from control and insulin-treated rats were fractionated and assayed for inhibition of protein phosphorylation by cyclic adenosine monophosphate (AMP)-dependent and -independent protein kinases. A differential effect of insulin on a particular fraction was observed on cyclic AMP-dependent protein kinase but not on cyclic AMP-independent protein kinases. This fraction that inhibited cyclic AMP-dependent protein kinase also stimulated glycogen synthase phosphoprotein phosphatase. It is proposed that this fraction may contain a mediator substance generateed in the presence of insulin.

Monoclonal antibodies with an apparent specificity for human small-cell carcinoma, adenocarcinoma, and squamous carcinoma of the lung are produced by some hybridomas obtained from mice and rats immunized with an established line of human small cell lung cancer. Out of 85 of these antibodies produced by independently isolated hybridomas from 15 different fusions, 21 are directed against the sugar sequence which occurs in lacto- N -fucopentaose III ceramide, in several higher glycolipids and in glycoproteins. Specificity was determined by autoradiography of thin-layer chromatograms of glycolipids, by solid-phase radioimmunoassays, and by hapten inhibition studies. All 21 antibodies are of the immunoglobulin M type.

On the basis of the chemical and structural features of the amino acid sequences in the vicinities of phosphorylatable hydroxyamino acid residues in several of the well-known protein substrates for skeletal-muscle cyclic AMP-dependent protein kinase, it is hypothesized that the phosphorylatable residue at position i and arginine residue at position i-3 of these protein substrates are located on a peptide turn on the hydrophilic protein surface. It is further hypothesized that there is an arginine-recognition site near the active centre on the protein kinase. This site is essential for the function of cyclic AMP-dependent protein kinase, for, not only does it recognize specifically the exposed arginine residue of the protein substrate, but, more importantly, via the interaction with arginine-(i′3), it may help to steer the topologically adjacent serine-i into proper orientation on the nearby active centre for phosphorylation. Model-building and kinetic data that provide support for the proposed hypotheses are presented.

We have detailed two separate mechanisms for insulin to activate glycogen synthase. In mechanism I, insulin acts without glucose present via a mediator to convert the cyclic AMP-dependent protein kinase to a desensitized holoenzyme, effectively lowering the response of the cell machinery to existing concentrations of cyclic AMP. Mechanism II, originally discovered in rat adipocytes, is seen in the presence of glucose, or of a hexose whose transport is accelerated by insulin. Enhanced phosphorylation of the 6 position is also required, since the hexose-6-phosphate acts informationally to activate the phospho-protein phosphatase to convert glycogen synthase to its dephospho state. Today I should like to discuss recent findings of our laboratory which demonstrate the presence of mechanism II in muscle, namely, mouse diaphragm, pointing out the generality of this mechanism and discuss our recent studies on the identification of insulin mediators which control protein phosphorylation state.

A group of monoclonal antibodies was shown to react with glycoconjugates containing a sugar sequence--lacto-N-fucopentaose III (LNF-III)--in granulocytes and in some normal nonlymphoid cells. The antibodies including anti-Leu M1, anti-My-1, WGHS 29-1, 534F-8, and 538F-12 of the immunoglobulin M-type were used to study the biochemical properties of LNF-III antigens in granulocytes, interdigitating reticulum cells, and neoplastic cells of Hodgkin's disease. In contrast to the presence of an abundant LNF-III glycolipid in granulocytes, the Hodgkin's neoplastic cells had no LNF-III glycolipid or contained only minimal amounts; however, both LNF-III glycoconjugates isolated from Hodgkin's neoplastic cells and interdigitating reticulum cells appeared to be a similar, if not an identical, 150,000-molecular-weight glycoprotein. The neoplastic cells in Hodgkin's disease appeared to show a biochemical property more closely related to interdigitating reticulum cells than any other cells in the monocyte-granulocyte-histiocyte system.

SUMMARY Insulin treatment significantly altered the elution profile of deproteinized muscle extracts chromato-graphed on Sephadex G-25 columns, particularly in fraction II, which contains the insulin mediator. Further purification of fraction II by high-voltage paper electrophoresis at pH 1.9 and 3.5 resulted in two active fractions. Fraction 1 → 4 stimulated the cyclic AMP-dependent protein kinase and inhibited glycogen synthase phosphoprotein phosphatase, and may be a novel substance. Fractions 1 → > 6 and 3 → 6 inhibited the cyclic AMP-dependent protein kinase and stimulated glycogen synthase phosphatase. It is proposed that the insulin mediator is present in fractions 1 → 6 and 3 → 6.

Mice were immunized with purified eosinophils obtained from patients with the idiopathic hypereosinophilic syndrome. A hybridoma initially producing an IgM antibody which switched to an IgG1 antibody was selected for cloning and further testing. This IgG1 antibody reacted with human eosinophils, granulocytes, monocytes and large granular lymphocytes, but did not react with T lymphocytes, B lymphocytes, platelets, erythrocytes, or a panel of human leukemia cells and cell lines. Bone marrow analysis revealed staining of myeloid precursor cells but not erythroid precursors or plasma cells. This IgG1 antibody had no effect on aggregation of granulocytes, lysozyme release, superoxide production, chemotaxis, or killing activity; however, there was some stimulation of beta-glucuronidase secretion. While the antibody did not augment the killing of Staphylococcus aureus by granulocytes, the antibody itself was bactericidal. By immunoprecipitation of granulocytes, eosinophils and monocytes, a molecule with a molecular weight of 95 kD was identified.

It has been established that insulin treatment of cells, isolated plasma membranes, or whole animals leads to the generation of low molecular weight mediators which serve as intermediates in the signalling pathway. At least two distinct classes of mediator have been described, based on differences in apparent molecular weight, isoelectric point and biological activity (Cheng, K., and Larner, J. (1985) Ann. Rev. Physiol. 45, 407-424). Recently, Saltiel's (Saltiel, A.R., and Cuatrecasas, P. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 5793-5797) and Mato's (Mato, J.M., Kelly, K.L., Abler, A., and Jarett, L. (1987) J. Biol. Chem. 262, 2131-2137) laboratories have described an insulin "modulator" which was apparently derived from glycosylphosphoinositol linker, similar to those known to anchor proteins to the external surface of the cell membrane (Low, M.G. (1987) Bioch. J. 244, 1-13). In this paper, we report that highly purified preparations of the insulin mediator which stimulates pyruvate dehydrogenase phosphatase contain mannose, galactosamine, and D-chiroinositol. These determinations are based upon analyses using paper chromatography and gas chromatography/mass spectroscopy. Nitrous acid deamination of the mediator resulted in release of inositol phosphate, indicating that the galactosamine and D-chiroinositol are linked. Although the presence of chiroinositol in modulator from H35 hepatoma cells has been recently reported (Mato, J.M., Kelly, K.L., Abler, A., Jarett, L., Corkey, B.E., Cashel, J.A., and Zopf, D. (1987) Bioch. Biophys. Res. Comm. 146, 764-770), the optical identity of the inositol remained unknown until the present report. Likewise, the presence of galactosamine rather than glucosamine in insulin mediator is a novel finding. These findings, coupled with those of Saltiel and Mato's groups, provide clear evidence for the existence of multiple forms of insulin mediators. Additionally, the results presented here afford further confirmation for the formation of insulin mediators from glycosyl-phosphoinositol linkers.

Protein kinase isolated from rabbit skeletal muscle can be reversibly converted from the cAMP dependent form to the indepent form by chaotropic salts and urea. A similar but irreversible conversion can also be induced by trypsin digestion of the holoenzyme. The dissociation of cAMP dependent protein kinase by low concentrations of thiocyanate raises the possibility of isolating both native regulatory and catalytic subunits. From various changes in enzymatic activity caused by urea and trypsin perturbation, it is proposed that the conversion of protein kinase from the cAMP dependent to the independent form is due primarily to preferential modification of the regulatory subunit of the holoenzyme.