The Increasing Burden of Emergency Department and Inpatient Consultations for "Papilledema"

BACKGROUND

Increasing incidence of idiopathic intracranial hypertension (IIH), overreported radiologic signs of intracranial hypertension, difficult access to outpatient neuro-ophthalmology services, poor insurance coverage, and medicolegal concerns have lowered the threshold for emergency department (ED) visits for "papilledema." Our objective was to examine referral patterns and outcomes of neuro-ophthalmology ED and inpatient consultations for concern for papilledema.

METHODS

At one university-based quaternary care center, all adults referred for "papilledema" over one year underwent a standardized ED "papilledema protocol." We collected patient demographics, final diagnoses, and referral patterns.

RESULTS

Over 1 year, 153 consecutive patients were referred for concern for papilledema. After papilledema protocol, 89 of 153 patients (58%) had bilateral optic disc edema, among whom 89% (79/89) had papilledema (intracranial hypertension). Of the 38 of 153 (25%) consultations for suspected disorder of intracranial pressure without previous fundus examination (Group 1), 74% (28/38) did not have optic disc edema, 21% (8/38) had papilledema, and 5% (2/38) had other causes of bilateral disc edema. Of the 89 of 153 (58%) consultations for presumed papilledema seen on fundus examination (Group 2), 58% (66/89) had confirmed papilledema, 17% (15/89) had pseudopapilledema, and 9% (8/89) had other causes of bilateral optic disc edema. Of the 26 of 153 (17%) patients with known IIH (Group 3), 5 had papilledema and 4 required urgent intervention. The most common diagnosis was IIH (58/79). Compared with IIH, patients with secondary causes of intracranial hypertension were older (P = 0.002), men (P < 0.001), not obese (P < 0.001), and more likely to have neurologic symptoms (P = 0.002).

CONCLUSION

Inpatient and ED consultations for "papilledema" are increasing. Of the 153 ED and inpatient neuro-ophthalmology consultations seen for "papilledema" over 1 year, one-third of patients with optic disc edema of unknown cause before presentation to our ED had new vision- or life-threatening disease, supporting the need for prompt identification and evaluation of optic disc edema in the ED. In the face of limited access to neuro-ophthalmologists, this study supports the need for emergency department access to expert eye-care evaluation or ocular fundus camera for prompt identification of optic disc edema and standardized evaluation for neurologic emergencies.

Optic Nerve MRI T2-Hyperintensity: A Nonspecific Marker of Optic Nerve Damage

BACKGROUND

MRI abnormalities are common in optic neuropathies, especially on dedicated orbital imaging. In acute optic neuritis, optic nerve T2-hyperintensity associated with optic nerve contrast enhancement is the typical imaging finding. In chronic optic neuropathies, optic nerve T2-hyperintensity and atrophy are regularly seen. Isolated optic nerve T2-hyperintensity is often erroneously presumed to reflect optic neuritis, frequently prompting unnecessary investigations and neuro-ophthalmology consultations. Our goal was to determine the significance of optic nerve/chiasm T2-hyperintensity and/or atrophy on MRI.

METHODS

Retrospective study of consecutive patients who underwent brain/orbital MRI with/without contrast at our institution between July 1, 2019, and June 6, 2022. Patients with optic nerve/chiasm T2-hyperintensity and/or atrophy were included. Medical records were reviewed to determine the etiology of the T2-hyperintensity and/or atrophy.

RESULTS

Four hundred seventy-seven patients (698 eyes) were included [mean age 52 years (SD ±18 years); 57% women]. Of the 364 of 698 eyes with optic nerve/chiasm T2-hyperintensity without atrophy, the causes were compressive (104), inflammatory (103), multifactorial (49), glaucoma (21), normal (19), and other (68); of the 219 of 698 eyes with optic nerve/chiasm T2-hyperintensity and atrophy, the causes were compressive (57), multifactorial (40), inflammatory (38), glaucoma (33), normal (7), and other (44); of the 115 of 698 eyes with optic nerve/chiasm atrophy without T2-hyperintensity, the causes were glaucoma (34), multifactorial (21), inflammatory (13), compressive (11), normal (10), and other (26). Thirty-six eyes with optic nerve/chiasm T2-hyperintensity or atrophy did not have evidence of optic neuropathy or retinopathy on ophthalmologic examination, and 17 eyes had clinical evidence of severe retinopathy without primary optic neuropathy.

CONCLUSIONS

Optic nerve T2-hyperintensity or atrophy can be found with any cause of optic neuropathy and with severe chronic retinopathy. These MRI findings should not automatically prompt optic neuritis diagnosis, workup, and treatment, and caution is advised regarding their use in the diagnostic criteria for multiple sclerosis. Cases of incidentally found MRI optic nerve T2-hyperintensity and/or atrophy without a known underlying optic neuropathy or severe retinopathy are rare. Such patients should receive an ophthalmologic examination before further investigations.

Glaucoma as a cause of optic nerve abnormalities on magnetic resonance imaging

BACKGROUND/OBJECTIVES

To report a series of patients with glaucoma and optic nerve abnormalities on magnetic resonance imaging (MRI) in at least one-eye, and to determine whether these findings correlate with the severity of glaucoma.

PATIENTS AND METHODS

Retrospective study of all patients who underwent a brain/orbits MRI without and with contrast at our institution between 07/1/2019-6/30/2022. Patients with optic nerve T2-hyperintensity and/or MRI optic nerve atrophy in at least one-eye and a diagnosis of isolated glaucoma in at least one-eye were included. Demographic information, glaucoma clinical characteristics, glaucoma severity parameters, and MRI indication were collected.

RESULTS

Fifty-six patients (112 eyes) (age 65 years-old [range 26-88]; 70% male) had isolated bilateral glaucoma with at least one-eye MRI optic nerve abnormality. The indication for MRI was atypical/asymmetric glaucoma in 91% of patients. Of the 112 eyes, 23 had optic nerve T2-hyperintensity alone; 33 had both optic nerve T2-hyperintensity and MRI optic nerve atrophy; 34 had MRI optic nerve atrophy alone; and 22 did not have abnormal optic nerve MRI-findings. None had optic nerve enhancement. A statistically significant association between optic nerve T2-hyperintensity or MRI optic nerve atrophy and glaucoma severity parameters was found.

CONCLUSIONS

Glaucoma is a clinical diagnosis and MRI brain is usually not required, except in atypical or asymmetric cases. Optic nerve T2-hyperintensity and MRI optic nerve atrophy are nonspecific MRI-findings that can be found in severe glaucomatous optic nerves and should not systematically prompt investigations for another cause of optic neuropathy.

A multi-centre case series of patients with coexistent intracranial hypertension and malignant arterial hypertension

OBJECTIVE

To describe the clinical characteristics, outcomes, and management of a large cohort of patients with concomitant malignant arterial hypertension and intracranial hypertension.

METHODS

Design: Retrospective case series.

SUBJECTS

Patients aged ≥ 18 years with bilateral optic disc oedema (ODE), malignant arterial hypertension and intracranial hypertension at five academic institutions. Patient demographics, clinical characteristics, diagnostic studies, and management were collected.

RESULTS

Nineteen patients (58% female, 63% Black) were included. Median age was 35 years; body mass index (BMI) was 30 kg/m2. Fourteen (74%) patients had pre-existing hypertension. The most common presenting symptom was blurred vision (89%). Median blood pressure (BP) was 220 mmHg systolic (IQR 199-231.5 mmHg) and 130 mmHg diastolic (IQR 116-136 mmHg) mmHg), and median lumbar puncture opening pressure was 36.5 cmH2O. All patients received treatment for arterial hypertension. Seventeen (89%) patients received medical treatment for raised intracranial pressure, while six (30%) patients underwent a surgical intervention. There was significant improvement in ODE, peripapillary retinal nerve fibre layer thickness, and visual field in the worst eye (p < 0.05). Considering the worst eye, 9 (47%) presented with acuity ≥ 20/25, while 5 (26%) presented with ≤ 20/200. Overall, 7 patients maintained ≥ 20/25 acuity or better, 6 demonstrated improvement, and 5 demonstrated worsening.

CONCLUSIONS

Papilloedema and malignant arterial hypertension can occur simultaneously with potentially greater risk for severe visual loss. Clinicians should consider a workup for papilloedema among patients with significantly elevated blood pressure and bilateral optic disc oedema.

Neuro-ophthalmology Emergency Department and Inpatient Consultations at a Large Academic Referral Center

PURPOSE

Prompt neuro-ophthalmology consultation prevents diagnostic errors and improves patient outcomes. The scarcity of neuro-ophthalmologists means that the increasing outpatient demand cannot be met, prompting many emergency department (ED) referrals by non-neuro-ophthalmologists. We describe our quaternary care institution's ED and inpatient neuro-ophthalmology consultation patterns and patient outcomes.

DESIGN

Prospective observational study.

PARTICIPANTS

Consecutive neuro-ophthalmology ED and inpatient consultation requests over 1 year.

METHODS

We collected patient demographics, distance traveled, insurance status, referring provider details, consultation question, final diagnosis, complexity of consultation, time of consultation, and need for outpatient follow-up.

MAIN OUTCOME MEASURES

Consultation patterns and diagnoses, complexity, and follow-up.

RESULTS

Of 494 consecutive adult ED and inpatient neuro-ophthalmology consultations requested over 1 year, 241 of 494 consultations (49%) occurred at night or during weekends. Of ED consultations (322 of 494 [65%]), 127 of 322 consultations (39%) occurred during weekdays, 126 of 322 consultations (39%) occurred on weeknights, and 69 of 322 consultations (22%) occurred on weekends or holidays. Of 322 ED consultations, 225 of 322 consultations (70%) were patients who initially sought treatment in the ED with a neuro-ophthalmic chief symptom. Of the 196 patients sent to the ED by a health care professional, 148 patients (148/196 [76%]) were referred by eye care specialists (74 optometrists and 74 ophthalmologists). The most common ED referral questions were for papilledema (75 of 322 [23%]) and vision loss (72 of 322 [22%]). A total of 219 of 322 patients (68%) received a final active neuro-ophthalmic diagnosis, 222 of 322 patients (69%) were cases of high or very high complexity, and 143 of 322 patients (44%) required admission. Inpatient consultations (n = 172) were requested most frequently by hospitalists, including neurologists (71 of 172 [41%]) and oncologists (20 of 172 [12%]) for vision loss (43 of 172 [25%]) and eye movement disorders (36 of 172 [21%]) and by neurosurgeons (58 of 172 [33%]) for examination for mass or a preoperative evaluation (19 of 172 [11%]). An active neuro-ophthalmic diagnosis was confirmed in 67% of patients (116 of 172). Outpatient neuro-ophthalmology follow-up was required for 291 of 494 patients (59%).

CONCLUSIONS

Neuro-ophthalmology consultations are critical to the diagnosis and management in the hospital setting. In the face of a critical shortage of neuro-ophthalmologists, this study highlights the need for technological and diagnostic aids for greater outpatient access.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Optometric Practice Patterns for Acute Central and Branch Retinal Artery Occlusion

BACKGROUND

Optometrists are often the first providers to evaluate patients with acute vision loss and are often the first to diagnose a central retinal artery occlusion (CRAO). How quickly these patients present to the optometrist, are diagnosed, and referred for evaluation are major factors influencing the possibility of acute therapeutic intervention. Our aim was to survey the U.S. optometric community to determine current optometric practice patterns for management of CRAO.

METHODS

An anonymous seven-question survey was emailed in 2020 to the 5,101 members of the American Academy of Optometry and the 26,502 members of the American Optometric Association.

RESULTS

Of 31,603 optometrists who were sent the survey, 1,926 responded (6.1%). Most respondents (1,392/1,919, 72.5%) worked in an optometry-predominant outpatient clinic and were less than 30 minutes from a certified stroke center (1,481/1,923, 77.0%). Ninety-eight percent (1,884/1,922) of respondents had diagnosed less than 5 CRAOs in the previous year, and 1,000/1,922 (52.0%) had not diagnosed a CRAO in the prior year. Of the optometrists who diagnosed at least one CRAO in the previous year, 661/922 (71.7%) evaluated these patients more than 4 hours after the onset of vision loss. Optometrists who diagnosed a CRAO or branch retinal artery occlusion referred patients to an emergency department (ED) affiliated with a certified stroke center (844/1,917, 44.0%), an outpatient ophthalmology clinic (764/1,917, 39.9%), an ED without a stroke center (250/1,917, 13.0%), an outpatient neurology clinic (20/1,917, 1.0%), or other (39/1,917, 2.0%); most (22/39, 56.4%) who responded "other" would refer to a primary care physician.

CONCLUSIONS

Optometrists are likely the first providers to evaluate patients with acute vision loss, including from a retinal artery occlusion. However, only 6.1% of optometrists responded to our survey despite 2 reminder emails, likely reflecting the lack of exposure to acute retinal artery occlusions, and a potential lack of interest of optometrists in participating in research. Of the optometrists who reported evaluating a CRAO in the previous year, less than 29% saw the patient within 4 hours of vision loss. In addition, a large portion of optometrists are referring acute CRAO patients to outpatient ophthalmology clinics, delaying appropriate acute management. Therefore, it is imperative that optometrists and ophthalmologists are educated to view acute retinal arterial ischemia as an acute stroke and urgently refer these patients to an ED affiliated with a stroke center. The delay in patient presentation and these referral patterns make future clinical trials for acute CRAO challenging.

Noninvasive methods to monitor intracranial pressure

PURPOSE OF REVIEW

Intracranial pressure (ICP) is determined by the production of and outflow facility of cerebrospinal fluid. Since alterations in ICP are implicated in several vision-threatening and life-threatening diseases, measurement of ICP is necessary and common. All current clinical methods to measure ICP are invasive and carry the risk for significant side effects. Therefore, the development of accurate, reliable, objective, and portal noninvasive devices to measure ICP has the potential to change the practice of medicine. This review discusses recent advances and barriers to the clinical implementation of noninvasive devices to determine ICP.

RECENT FINDINGS

Many noninvasive methods to determine ICP have been developed. Although most have significant limitations limiting their clinical utility, several noninvasive methods have shown strong correlations with invasively obtained ICP and have excellent potential to be developed further to accurately quantify ICP and ICP changes.

SUMMARY

Although invasive methods remain the mainstay for ICP determination and monitoring, several noninvasive biomarkers have shown promise to quantitatively assess and monitor ICP. With further refinement and advancement of these techniques, it is highly possible that noninvasive methods will become more commonplace and may complement or even supplant invasively obtained methods to determine ICP in certain situations.

Evidence for Menopause as a Sex-Specific Risk Factor for Glaucoma

Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by progressive loss of visual function and retinal ganglion cells (RGC). Current epidemiological, clinical, and basic science evidence suggest that estrogen plays a role in the aging of the optic nerve. Menopause, a major biological life event affecting all women, coincides with a decrease in circulating sex hormones, such as estrogen. While 59% of the glaucomatous population are females, sex is not considered a risk factor for developing glaucoma. In this review, we explore whether menopause is a sex-specific risk factor for glaucoma. First, we investigate how menopause is defined as a sex-specific risk factor for other pathologies, including cardiovascular disease, osteoarthritis, and bone health. Next, we discuss clinical evidence that highlights the potential role of menopause in glaucoma. We also highlight preclinical studies that demonstrate larger vision and RGC loss following surgical menopause and how estrogen is protective in models of RGC injury. Lastly, we explore how surgical menopause and estrogen signaling are related to risk factors associated with developing glaucoma (e.g., intraocular pressure, aqueous outflow resistance, and ocular biomechanics). We hypothesize that menopause potentially sets the stage to develop glaucoma and therefore is a sex-specific risk factor for this disease.

Unilateral Isolated Paucisymptomatic Optic Disc Edema

BACKGROUND

Unilateral isolated optic disc edema (UIODE) represents a challenging clinical presentation that frequently precipitates an extensive diagnostic work-up. Patients without an apparent diagnosis despite appropriate investigations are often categorized as having "papillophlebitis," an entity that is poorly defined in the existing literature. Our aim was to describe the characteristics of a series of patients with paucisymptomatic UIODE, determine the optimal diagnostic approach to such cases, and clarify the clinical features of presumed papillophlebitis.

METHODS

We retrospectively identified 29 patients with UIODE who were seen by neuro-ophthalmologists at a single center between 2005 and 2019. Each patient presented with isolated, unilateral disc edema that was either entirely asymptomatic or associated with minimal visual symptoms. Patients underwent a comprehensive neuro-ophthalmic evaluation and several ophthalmic and systemic investigations. Data from the initial visit and all subsequent clinical visits were collected, including patient demographics, examination findings, and details of the diagnostic work-up.

RESULTS

Our 29 patients with UIODE were found to have a variety of underlying diagnoses including unilateral papilledema due to idiopathic intracranial hypertension (10 patients), optic nerve sheath meningioma (5), incipient nonarteritic anterior ischemic neuropathy (4), vitreopapillary traction (3), orbital masses (2), a peripapillary choroidal neovascular membrane (1), and presumed papillophlebitis (4). The duration of disc edema varied considerably based on the etiology, but most patients had favorable visual outcomes.

CONCLUSIONS

A systematic approach to the evaluation of UIODE, combined with long-term follow-up, led to a definite diagnosis in a majority of patients, with only 4 patients presumed to have papillophlebitis, a diagnosis the actual existence of which remains controversial.

An unusual presentation of neurosarcoidosis: Concurrent optic perineuritis and optic neuritis

Neurosarcoidosis is a rare complication of sarcoidosis and typically presents as acute cranial neuropathies. Neurosarcoidosis can rarely cause an inflammatory optic neuropathy, resembles an optic neuritis and even more rarely can cause an optic perineuritis. Although concomitant optic neuritis and optic perineuritis have been reported in other inflammatory conditions, such as myelin oligodendrocyte antibody-associated disease, spatially-distinct optic neuritis, and optic perineuritis has not been previously described in neurosarcoidosis. Here, we present a case of spatially-distinct concomitant optic neuritis and optic perineuritis from neurosarcoidosis in a 51-year-old man initially suspected to harbor metastatic disease based on imaging findings.

Very Poor Visual Acuity in Non-Arteritic Anterior Ischaemic Optic Neuropathy

Very poor (hand motion or worse) visual acuity at presentation is highly unusual in non-arteritic anterior ischaemic optic neuropathy. We retrospectively reviewed the medical records of 151 consecutive non-arteritic anterior ischaemic optic neuropathy patients seen at our institution between July 2014 and April 2016 to evaluate the frequency and characteristics of patients with very poor visual acuity in non-arteritic anterior ischaemic optic neuropathy. Hand motion or worse visual acuity was documented in 17 patients (11%); all patients had at least one vascular risk factor and 14 (82%) had at least two vascular risk factors. Although severe vision loss at presentation does occur in non-arteritic anterior ischaemic optic neuropathy, an extensive workup should be obtained to rule out another cause, especially arteritic anterior ischaemic optic neuropathy.

Spontaneous Skull Base Cerebrospinal Fluid Leaks and Their Relationship to Idiopathic Intracranial Hypertension

Background

The association between spontaneous skull base cerebrospinal fluid (CSF) leaks and idiopathic intracranial hypertension (IIH) has been suggested, but its significance remains unclear.

Objective

To estimate the prevalence of IIH in spontaneous skull base CSF leak patients.

Methods

Systematic collection of demographics, neuro-ophthalmic and magnetic resonance imaging evaluation of spontaneous skull base CSF leak patients seen pre- and post-leak repair in one neuro-ophthalmology service. Patients with preexisting IIH were diagnosed with definite IIH if adequate documentation was provided; otherwise, they were categorized with presumed IIH. Classic radiographic signs of intracranial hypertension and bilateral transverse venous sinus stenosis were recorded.

Results

Thirty six patients were included (age [interquartile range]: 50 [45;54] years; 94% women; body mass index: 36.8 [30.5;39.9] kg/m2), among whom six (16.7%, [95% confidence interval, CI]: [6.4;32.8]) had a preexisting diagnosis of definite or presumed IIH. Of the remaining 30 patients, four (13.3%, 95%CI: [3.8;30.7]) had optic nerve head changes suggesting previously undiagnosed IIH, while one was newly diagnosed with definite IIH at initial consultation. One out of 29 patients with normal findings of the optic nerve head at presentation developed new onset papilledema following surgery (3.4%, 95%CI: [0.1;17.8]) and was ultimately diagnosed with definite IIH. Overall, the prevalence of definite IIH was 19.4% (95%CI: [8.2;36.0]).

Conclusion

Striking demographic overlap exists between IIH patients and those with spontaneous CSF leak. Definite IIH was present in approximately 20% of our patients. However, its true prevalence is likely higher than identified by using classic criteria. We therefore hypothesize that an active CSF leak serves as an auto-diversion for CSF, thereby “treating” the intracranial hypertension and eliminating characteristic signs and symptoms at initial presentation.

Micronutrients in support to the one carbon cycle for the modulation of blood fasting homocysteine in PCOS women

PURPOSE

Fasting blood homocysteine is increased in PCOS women and is involved in several of its co-morbidities including cardiovascular disease and infertility. Corrective interventions based on the administration of supra-physiologic doses of folic acid work to a low extent. We aimed to test an alternative approach.

METHODS

This was a prospective, randomized, parallel group, open label, controlled versus no treatment clinical study. PCOS women aged > 18, free from systemic diseases and from pharmacological treatments were randomized with a 2:1 ratio for treatment with activated micronutrients in support to the carbon cycle (Impryl, Parthenogen, Switzerland-n = 22) or no treatment (n = 10) and followed-up for 3 months. Fasting blood homocysteine, AMH, testosterone, SHBGs, and the resulting FTI were tested before and at the end of the follow-up.

RESULTS

The mean baseline fasting blood homocysteine was above the normal limit of 12 μMol/L and inversely correlated with SHBG. AMH was also increased, whereas testosterone, SHBG, and FTI were within the normal limit. The treatment achieved a significant reduction of homocysteine, that did not change in the control group, independently of the starting value. The treatment also caused an increase of AMH and a decrease of SHBGs only in the subgroup with a normal homocysteine at baseline.

CONCLUSIONS

In PCOS ladies, blood homocysteine is increased and inversely correlated with the SHBGs. Physiologic amounts of activated micronutrients in support to the carbon cycle achieve a reduction virtually in all exposed patients. Whether this is of clinical benefit remains to be established.

Lack of Relationship between Central Corneal Thickness and Papilloedema in Idiopathic Intracranial Hypertension

Translaminar pressure gradient abnormalities have been implicated in the pathogenesis and progression of glaucoma. A "reversed" translaminar pressure gradient may be related to papilloedema severity in idiopathic intracranial hypertension. Central corneal thickness is related to intraocular pressure measurements and, by extension, to translaminar pressure gradients. We evaluated if central corneal thickness could be a marker of worse papilloedema due to altered translaminar pressure gradients in patients with idiopathic intracranial hypertension. We found that central corneal thickness was not related to the severity of papilloedema in idiopathic intracranial hypertension.

Regulation of TRPC5 currents by intracellular ATP: Single channel studies

TRPC5 channels are nonselective cation channels activated by G-protein-coupled receptors. It was previously found that recombinant TRPC5 currents are inhibited by intracellular ATP, when studied by whole-cell patch-clamp recording. In the present study, we investigated the mechanism of ATP inhibition at the single-channel level using patches from HEK-293 cells transiently transfected with TRPC5 and the M1 muscarinic receptor. In inside-out patches, application of ATP to the intracellular face of the membrane reduced TRPC5 channel activity at both positive and negative potentials without affecting the unitary current amplitude or open dwell time of the channel. The effect of ATP was rapidly reversible. These results suggest that ATP may bind to the channel protein and affect the ability of the channel to open or to remain in an open, nondesensitized state. The activity of TRPC5 channels may be influenced by cellular metabolism via changes in ATP levels.

Detection and characterization of tree shrew retinal venous pulsations: An animal model to study human retinal venous pulsations

Spontaneous retinal venous pulsations (SRVPs), pulsations of branches of the central retinal vein, are affected by intraocular pressure (IOP) and intracranial pressure (ICP) and thus convey potentially-useful information about ICP. However, the exact relationship between SRVPs, IOP, and ICP is unknown. It is not easily feasible to study this relationship in humans, necessitating the use of an animal model. We here propose tree shrews as a suitable animal model to study the complex relationship between SRVPs, IOP, and ICP. Tree shrew SRVP incidence was determined in a population of animals. Following validation of a modified IOP control system to accurately and quickly control IOP, IOP and/or ICP were manipulated in two tree shrews with SRVPs and the effects on SRVP properties were quantified. SRVPs were present in 75% of tree shrews at physiologic IOP and ICP. Altering IOP or ICP produced changes in tree shrew SRVP properties; specifically, increasing IOP caused SRVP amplitude to increase, while increasing ICP caused SRVP amplitude to decrease. In addition, a higher IOP was necessary to generate SRVPs at a higher ICP than at a lower ICP. SRVPs occur with a similar incidence in tree shrews as in humans, and tree shrew SRVPs are affected by changes in IOP and ICP in a manner qualitatively similar to that reported in humans. In view of anatomic similarities, tree shrews are a promising animal model system to further study the complex relationship between SRVPs, IOP, and ICP.

Treatment of Nonarteritic Acute Central Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) is an event most often caused by an embolus originating in the ipsilateral carotid artery, aortic arch, or heart. CRAO may result from partial or complete occlusion of the central retinal artery (CRA), which acts as the primary blood supply to the inner neurosensory retina, and typically results in profound vision loss and permanent visual disability. No consensus has emerged regarding the optimal treatment of CRAO. All proposed treatments are of questionable efficacy and many have uncertain risk profiles. In certain circumstances, thrombolysis may be attempted as a treatment option; however, the evidence to support broad use of thrombolytics in the treatment of acute CRAO remains elusive. It is known that the risk factors that predispose to other cardiovascular and cerebrovascular events are often present in CRAO. Accordingly, identification of patients at highest risk of stroke and secondary prevention of ischemic events remains the primary focus of management. This review offers a summary of the clinical presentation, diagnosis, and prognosis of CRAO, with an emphasis on treatment options.

Acute retinal arterial ischemia

Acute retinal arterial ischemia, which includes transient monocular vision loss (TMVL), branch retinal artery occlusion (BRAO), central retinal artery occlusion (CRAO) and ophthalmic artery occlusion (OAO), is most commonly the consequence of an embolic phenomenon from the ipsilateral carotid artery, heart or aortic arch, leading to partial or complete occlusion of the central retinal artery (CRA) or its branches. Acute retinal arterial ischemia is the ocular equivalent of acute cerebral ischemia and is an ophthalmic and medical emergency. Patients with acute retinal arterial ischemia are at a high risk of having further vascular events, such as subsequent strokes and myocardial infarctions (MIs). Therefore, prompt diagnosis and urgent referral to appropriate specialists and centers is necessary for further work-up (such as brain magnetic resonance imaging with diffusion weighted imaging, vascular imaging, and cardiac monitoring and imaging) and potential treatment of an urgent etiology (e.g., carotid dissection or critical carotid artery stenosis). Since there are no proven, effective treatments to improve visual outcome following permanent retinal arterial ischemia (central or branch retinal artery occlusion), treatment must focus on secondary prevention measures to decrease the likelihood of subsequent ischemic events.

Update on the Management of Central Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) is caused by partial or complete occlusion of the central retinal artery, most commonly by an embolus from the ipsilateral carotid artery, aortic arch, or heart, and is the ocular equivalent of an acute cerebral ischemic event. The risk factors for a CRAO and acute cerebral ischemia are very similar, if not identical. Because no current therapeutic intervention has been shown to improve visual outcomes compared with the natural history of CRAO, management of CRAO should be focused on secondary prevention of vascular events, such as cerebral ischemia, myocardial infarction, and cardiovascular death.

The expression and function of netrin-4 in murine ocular tissues

Netrin-4, a member of the netrin family, is a potent regulator of embryonic development. It promotes neurite extension and regulates pulmonary airway branching, vasculogenesis patterning, and endothelial proliferation in pathological angiogenesis. The initial characterization of netrin-4 expression was focused on epithelial-derived organs (kidney, lung and salivary gland) and the central nervous system. Ocular development is an ideal system to study netrin-4 expression and function, as it involves both ectodermal (cornea, lens and retina) and mesodermal (sclera and choroid) derivatives and has an extensive and well-characterized angiogenic process. Netrin-4 is expressed in all ocular tissues. It is a prominent component of the basement membranes of the lens and cornea, as well as all three basement membranes of the retina: the inner limiting membrane, vascular basement membranes, and Bruch's membrane. Netrin-4 is differentially deposited in vascular basement membranes, with more intense anti-netrin-4 reactivity on the arterial side. The retinal microcirculation also expresses netrin-4. In order to test the function of netrin-4 in vivo, we generated a conventional mouse lacking Ntn4 expression. Basement membrane formation in the cornea, lens and retina is undisrupted by netrin-4 deletion, demonstrating that netrin-4 is not a major structural component of these basement membranes. In the Ntn4 homozygous null (Ntn4-/-) cornea, the overall morphology of the cornea, as well as the epithelial, stromal and endothelial stratification are normal; however, epithelial cell proliferation is increased. In the Ntn4-/- retina, neurogenesis appears to proceed normally, as does retinal lamination. In the Ntn4-/- retina, retinal ganglion cell targeting is intact, although there are minor defects in axon fasciculation. In the retinal vasculature of the Ntn4-/- retina, the distribution patterns of astrocytes and the vasculature are largely normal, with the possible exception of increased branching in the deep capillary plexus, suggesting that netrin-4 may act as a negative regulator of angiogenesis. These data, taken together, suggest that netrin-4 is a negative regulator of corneal epithelial cell proliferation and retinal vascular branching in vivo, whereas netrin-4 may be redundant with other members of the netrin family in other ocular tissue development. Ntn4-/- mice may serve as a good model in which to study the role of netrins in vivo of the pathobiologic vascular remodeling in the retina and cornea.

Sleep and muscle recovery: endocrinological and molecular basis for a new and promising hypothesis

Sleep is essential for the cellular, organic and systemic functions of an organism, with its absence being potentially harmful to health and changing feeding behavior, glucose regulation, blood pressure, cognitive processes and some hormonal axes. Among the hormonal changes, there is an increase in cortisol (humans) and corticosterone (rats) secretion, and a reduction in testosterone and Insulin-like Growth Factor 1, favoring the establishment of a highly proteolytic environment. Consequently, we hypothesized that sleep debt decreases the activity of protein synthesis pathways and increases the activity of degradation pathways, favoring the loss of muscle mass and thus hindering muscle recovery after damage induced by exercise, injuries and certain conditions associated with muscle atrophy, such as sarcopenia and cachexia.

Inhibition of TRPC5 channels by intracellular ATP

TRPC5 channels are Ca(2+)-permeable nonselective cation channels activated by G-protein-coupled receptors, although the mechanisms responsible for channel activation and regulation are poorly understood. Carbachol-activated TRPC5 currents were recorded by the whole-cell patch clamp technique from human embryonic kidney 293 cells transiently transfected with TRPC5 and the M1 muscarinic receptor. Some published studies of TRPC5 currents have included ATP and/or GTP in the patch pipette, whereas others used an ATP- and GTP-free pipette solution. We initially included these two nucleotides in the patch pipette but found that TRPC5 currents were absent or were very small. Recordings made with an ATP- and GTP-free pipette solution produced large and robust TRPC5 currents. Under these conditions, treatment of cells with Pasteurella multocida toxin, a selective inhibitor of Galpha(q), almost abolished TRPC5 currents indicating that Galpha(q) is necessary for activation of TRPC5 by the M1 receptor. To study the effect of intracellular ATP on TRPC5 channels, an intracellular perfusion system was used. Perfusion of ADP or control pipette solution had no effect, whereas perfusion of ATP or AMP-PNP, a nonhydrolyzable analog of ATP, significantly inhibited TRPC5 currents. Thus, the effects of ATP have structural specificity and probably involve a direct effect on the channel rather than a phosphorylation-mediated effect. The activity of TRPC5 channels may be linked to cellular metabolism via changes in ATP levels and could be involved in Ca(2+) overload occurring after ischemia when ATP is depleted.

Reversal of neurosteroid effects at alpha4beta2delta GABAA receptors triggers anxiety at puberty

Puberty is characterized by mood swings and anxiety, which are often produced by stress. Here we show that THP (allopregnanolone), a steroid that is released as a result of stress, increases anxiety in pubertal female mice, in contrast to its anxiety-reducing effect in adults. Anxiety is regulated by GABAergic inhibition in limbic circuits. Although this inhibition is increased by THP administration before puberty and in adults, during puberty THP reduces the tonic inhibition of pyramidal cells in hippocampal region CA1, leading to increased excitability. This paradoxical effect of THP results from inhibition of alpha4betadelta GABAA receptors. These receptors are normally expressed at very low levels, but at puberty, their expression is increased in hippocampal area CA1, where they generate outward currents. THP also decreases the outward current at recombinant alpha4beta2delta receptors, and this effect depends on arginine 353 in the alpha4 subunit, a putative site for modulation by Cl-. Therefore, inhibition of alpha4beta2delta GABAA receptors by THP provides a mechanism for the generation of anxiety at puberty.

Pharmacology of delta2 glutamate receptors: effects of pentamidine and protons

The properties of delta2 receptors, which have homology to glutamate receptors but are not gated by glutamate, were studied using the constitutively active Lurcher mutant delta2(A654T) expressed in Xenopus oocytes. The macroscopic current through delta2(A654T) channels in voltage-clamped oocytes was defined as the difference between the holding current measured in the presence of extracellular Na(+) and that in the presence of the large impermeant cation N-methyl-d-glucamine. A-to-T mutations in the delta1 subunit and in NMDA (N-methyl-d-aspartate) receptor subunits, at positions equivalent to delta2(A654T), did not produce constitutively active channels. The current through delta2(A654T) channels was reduced by pentamidine and 9-tetrahydroaminoacridine, antagonists that also inhibit NR1/NR2B NMDA receptors but not AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptors. Block of delta2(A654T) currents by these two antagonists was incomplete and weakly voltage-dependent, in contrast to the block of NR1/NR2B receptors, which was complete and strongly voltage-dependent. Pentamidine inhibited a constitutively active NR1(T648A)/NR2B NMDA receptor in a manner similar to its inhibition of a glutamate-gated wild-type NMDA receptor, but different from its inhibition of constitutively active delta2(A654T) receptors. Currents gated by delta2(A654T) were sensitive to the extracellular pH, being smaller at acidic than at alkaline pH, with a pH IC(50) value of 7.47 and a maximum inhibition of 70%. It is concluded that delta2(A654T) channels have some properties in common with NMDA channels but also have characteristics that are different from these receptors. Compounds such as pentamidine may be useful for studies of native delta2 receptors.

Helicobacter pylori infection, chronic gastritis, and proton pump inhibitors

The proton pump inhibitors (PPIs) omeprazole, lansoprazole, and pantoprazole are widely used as antisecretory drugs and, in association with antibiotics, for the treatment of Helicobacter pylori infections. PPIs possess antibacterial activity against H. pylori in vitro, and may also exert an anti-inflammatory effect by interfering with the cellular immune response to infection. Their antimicrobial activity is selective for H. pylori. Lansoprazole is the most effective, although its bactericidal activity is similar to that of omeprazole. Pantoprazole is the least effective. The mechanisms that account for the antibacterial effects of PPIs may depend on a structural similarity of PPIs to antibiotics which are active against H. pylori, on the inhibition of bacterial urease exerted by PPIs, or on the possible interaction of PPIs with bacterial ATPases that regulate the transmembrane ion flux. Recent studies have shown that PPIs have anti-inflammatory actions and can interfere with the host-bacteria interactions. Lansoprazole can bind to polymorphonuclear leukocytes that infiltrate the gastric mucosa colonized by H. pylori and can thus inhibit the oxidative burst of activated inflammatory cells. In an in vivo study, lansoprazole reduced the degree of activity of histologic gastritis independently of the presence of H. pylori. In another study, omeprazole was capable of inhibiting the cytotoxic activity of NK T cells. Investigation of PPI interactions with H. pylori activities and the cellular immune response to the infection may help us to understand the pathogenic mechanisms of H. pylori-associated diseases and enable clinicians to better treat them.

Bedtime administration of lansoprazole does not modify its greater efficacy vs ranitidine in the acute and long-term treatment of duodenal ulcer. Results from a multicentre, randomised, double blind clinical trial

BACKGROUND/AIMS

The efficacy of proton pump inhibitors is considered linked to morning, fasting administration. The aim of the present study was to assess efficacy and tolerability of the proton pump inhibitors lansoprazole given at bedtime as compared to ranitidine, both in acute and maintenance treatment of duodenal ulcer.

METHODS

This was a randomised double blind study. The patients were divided into 4 treatment groups as follows (healing/maintenance): 1) lansoprazole 30 mg/lansoprazole 15 mg; 2) lansoprazole 30 mg/placebo; 3) ranitidine 300 mg/ranitidine 150 mg; 4) ranitidine 300 mg/placebo. Healing and relapse of ulcers were assessed by endoscopy at 2, 4 and 8 weeks and then at 3, 6, 9 and 12 months during follow-up.

RESULTS

A total of 132 patients were enrolled in 9 study centres. The cumulative healing rates (per-protocol analysis) at 2, 4 and 8 weeks were 57.4%, 83.9% and 89.2% in the lansoprazole group and 30%, 70.2% and 78.7% in the ranitidine group (p = 0.01 at 2 weeks). The 12-month cumulative relapse rate (intent-to-treat analysis) was lower in the lansoprazole/lansoprazole group (23.3%), than those reported by the other groups of patients lansoprazole/placebo (39.3%); ranitidine/ranitidine (45.8%); ranitidine/placebo (50%). The disease-free time from healing was significantly longer for lansoprazole treated patients (p < 0.05). All treatments were very well tolerated, only few minor adverse events being reported.

CONCLUSIONS

Lansoprazole maintains its greater efficacy vs ranitidine even when administered at bedtime, both for the healing and for the maintenance treatment of duodenal ulcer. Lansoprazole (half dose formulation) may be useful for the treatment of patients requiring long-term acid suppression.

A novel, simplified and cost effective protocol for superovulation and intrauterine insemination

OBJECTIVE

To determine the efficacy and cost of a simplified superovulation regimen compared with traditional control ovarian hyperstimulation with gonadotropins (HMG).

STUDY DESIGN

This was a retrospective study in a university referral center with 99 infertile couples undergoing 225 treatment cycles. The outcome was compared to outcomes of previously published studies. The simplified superovulation regimen included clomiphene citrate 100 mg on cycle days 5 through 9 and HMG 75 IU on cycle days 5, 7, 9, and 11, with estradiol and ultrasound monitoring on day 13. If adequate follicular maturity was documented, HCG 10,000 IU was administered, followed by intrauterine insemination 40 hours later.

RESULTS

Fecundity rates were assessed by life table analysis. Average cycle fecundity was 8%, with a cumulative rate of 29% over 4 cycles, compared to 10% monthly fecundity with HMG/IUI and background rates of 1 to 3%. Costs averaged $662 per cycle compared to $1,854 with HMG/IUI.

CONCLUSION

A simplified protocol of CC/HMG/ IUI is almost as effective as HMG/IUI and costs only one-third as much.

In-vitro activity of lansoprazole against Helicobacter pylori

Lansoprazole is a gastric parietal cell proton pump inhibitor that is also active against Helicobacter pylori in vitro. We aimed to investigate further the mechanism of its antimicrobial effect. The antimicrobial activity of lansoprazole and of its sulfenamide, a rearrangement product occurring spontaneously in acid environments, was studied by determining the MICs and MBCs for 11 cytotoxic and eight non-cytotoxic H. pylori strains and by measuring the rapidity of bacterial killing. The MIC90 and MBC90 were 2.5 mg/L and 10 mg/L, respectively, both for lansoprazole and for its sulfenamide. Cytotoxic strains were as susceptible as non-cytotoxic strains. The sulfenamide exhibited faster bactericidal activity. Lansoprazole did not inhibit the toxin-induced vacuolization of HeLa cells by a cytotoxic strain, hence its anti-H. pylori activity does not depend on inhibition of a v-ATPase-mediated, toxin-induced activity. Sulfenamide formation is likely to occur in vivo in the gastric environment, thus enhancing the bactericidal activity of the drug. Lansoprazole is likely to be useful, in association with antibiotics, in the treatment of H. pylori infection regardless of the cytotoxicity of the infecting strain.

Nicotinamide methylation in patients with cirrhosis

Methylation reactions play an important role in the transformation of endogenous and exogenous substances. Up to 85% of all transmethylation reactions occur in the liver. Several studies have shown that these metabolic processes are greatly influenced by the presence of hepatic diseases. We investigated the methylation of nicotinamide in 16 control subjects and in 29 patients with cirrhosis (19 Child A, 10 Child B). The basal serum value of N-methyl-nicotinamide was measured in all subjects. In seven controls and in nine patients with cirrhosis (5 Child A and 4 Child B), the serum levels and urinary excretion (5 and 24 h) of N-methyl-nicotinamide were also evaluated after oral administration of nicotinamide (1.5 mg/kg body weight). The basal serum levels of N-methyl-nicotinamide were significantly (p < 0.05) higher in patients with cirrhosis (Child A: median 34 ng/ml, 16th percentile 24, 84th percentile 61; Child B median 45, 16th percentile 34, 84th percentile 81) than in controls (median 22, 16th percentile 13, 85th percentile 28). After the nicotinamide load the urinary excretion and the time course of serum N-methyl-nicotinamide in cirrhosis were also higher (p < 0.05) than in controls (24 h urinary excretion = 66.2 mg +/- 5 S.D. in cirrhosis; 47.2 +/- 10.3 in controls) (area under the serum concentration versus time curve = 68 micrograms.ml-1.min-1 +/- 22 S.D. in cirrhosis; 32 +/- 15 in controls). In conclusion, our results show that cirrhosis does not impair the efficiency of nicotinamide methylation.

Intrauterine insemination. Effect of wash media on pregnancy rates and sperm motility

Testyolk Buffer has been shown to enhance sperm penetration in hamster penetration assays and increase fertilization of oocytes in in vitro fertilization. Based on these findings, we compared pregnancy rates and sperm motility in intrauterine inseminations done with sperm samples washed and resuspended in Ham's F10 as compared with Testyolk buffer. Charts were reviewed retrospectively from 1,098 husband and donor intrauterine inseminations performed at the University of Florida. Data were analyzed using life table analysis and the curves compared with the Mantel-Haenszel statistical test. In addition, sperm motility in fresh sperm was observed in samples incubated in Testyolk or Ham's F10, with motility counts performed at 0, 6 and 24 hours. Four hundred ninety-two Testyolk cycles and 579 Ham's F10 cycles were compared, with cumulative pregnancy rates at one year of 53% and 44%, respectively (P = .58). With donor sperm, 229 cycles with Testyolk and 314 cycles with Ham's F10 had cumulative pregnancy rates of 68% and 48%, respectively (P = .52). With husband insemination, 264 Testyolk and 253 Ham's F10 cycles had pregnancy rates of 37% and 35%, respectively (P = .23). Fresh sperm motility in 22 samples compared at 0, 6 and 24 hours in Ham's F10 (76%, 67.8%, 56.6%) versus Testyolk (76%, 67.7%, 58.8%) revealed no significant differences. There was also no difference in total motile sperm inseminated and postwash motility in 1,098 samples with Testyolk versus Ham's F10. This study demonstrates that there is no enhanced pregnancy rate or increased sperm motility when sperm are treated with Testyolk Buffer instead of Ham's F10.