Effects of hyperbaric exposure on eyes with intraocular gas bubbles

Air travel is known to be potentially hazardous for patients with intraocular gas bubbles (IGBs). These bubbles, which are used in the treatment of complicated retinal detachments, can last for up to a month depending on the combination of long-acting gases used. We hypothesized that the external pressure changes associated with hyperbaric oxygen therapy, SCUBA diving, or caisson work could be similarly dangerous. To test this, we placed IGBs into the right eyes of 18 rabbits and exposed them to several hyperbaric pressure profiles. In all profiles, the intraocular pressure (IOP) in the left or control eyes remained constant while the IOP in the eyes with the IGB dropped to zero on pressurization and increased to over 50 millimeters of mercury (mmHg) on depressurization. Pressures in excess of 50 mmHg were sustained for 10 minutes or longer. The mean peak IOP of the eyes with the IGBs as well as the mean time spent at an IOP of over 50 mmHg were both highly significant compared to that of the control groups (p\u3c0.001). This IGB-induced IOP response is caused by several mechanisms including continued vitreous and aqueous fluid inflow with decreased outflow during hypotony, bubble volume increase due to equilibration with higher partial pressures of oxygen and nitrogen, and choroidal engorgement with delayed draining at high IOPs. The magnitude and duration over 50 mmHg of the IOPs measured were enough to potentially cause severe pain, occlusion of the central retinal artery, and retinal ischemia. We therefore strongly advise against hyperbaric exposure for patients with IGBs

Management of Bladder Cancer following Solid Organ Transplantation

Objective. Present our experience managing bladder cancer following liver and renal transplantation. Methods. Single institution retrospective review of patients diagnosed with bladder urothelial carcinoma (BUC) following solid organ transplantation between January 1992 and December 2007. Results. Of the 2,925 renal and 2,761 liver transplant recipients reviewed, we identified eleven patients (0.2%) following transplant diagnosed with BUC. Two patients with low grade T1 TCC were managed by TURBT. Three patients with CIS and one patient with T1 low grade BUC were treated by TURBT and adjuvant BCG. All four are alive and free of recurrence at a mean follow-up of 51 ± 22 months. One patient with T1 high grade BUC underwent radical cystectomy and remains disease free with a follow-up of 98 months. Muscle invasive TCC was diagnosed in four patients at a median of 3.6 years following transplantation. Two patients are recurrence free at 24 and 36 months following radical cystectomy. Urinary diversion and palliative XRT were performed in one patient with un-resectable disease. Conclusions. Bladder cancer is uncommon following renal and liver transplantation, but it can be managed successfully with local and/or extirpative therapy. The use of intravesical BCG is possible in select immunosuppressed patients

A Synaptic Mechanism for Temporal Filtering of Visual Signals

The visual system transmits information about fast and slow changes in light intensity through separate neural pathways. We used in vivo imaging to investigate how bipolar cells transmit these signals to the inner retina. We found that the volume of the synaptic terminal is an intrinsic property that contributes to different temporal filters. Individual cells transmit through multiple terminals varying in size, but smaller terminals generate faster and larger calcium transients to trigger vesicle release with higher initial gain, followed by more profound adaptation. Smaller terminals transmitted higher stimulus frequencies more effectively. Modeling global calcium dynamics triggering vesicle release indicated that variations in the volume of presynaptic compartments contribute directly to all these differences in response dynamics. These results indicate how one neuron can transmit different temporal components in the visual signal through synaptic terminals of varying geometries with different adaptational properties

The ER-Bound RING Finger Protein 5 (RNF5/RMA1) Causes Degenerative Myopathy in Transgenic Mice and Is Deregulated in Inclusion Body Myositis

Growing evidence supports the importance of ubiquitin ligases in the pathogenesis of muscular disorders, although underlying mechanisms remain largely elusive. Here we show that the expression of RNF5 (aka RMA1), an ER-anchored RING finger E3 ligase implicated in muscle organization and in recognition and processing of malfolded proteins, is elevated and mislocalized to cytoplasmic aggregates in biopsies from patients suffering from sporadic-Inclusion Body Myositis (sIBM). Consistent with these findings, an animal model for hereditary IBM (hIBM), but not their control littermates, revealed deregulated expression of RNF5. Further studies for the role of RNF5 in the pathogenesis of s-IBM and more generally in muscle physiology were performed using RNF5 transgenic and KO animals. Transgenic mice carrying inducible expression of RNF5, under control of β-actin or muscle specific promoter, exhibit an early onset of muscle wasting, muscle degeneration and extensive fiber regeneration. Prolonged expression of RNF5 in the muscle also results in the formation of fibers containing congophilic material, blue-rimmed vacuoles and inclusion bodies. These phenotypes were associated with altered expression and activity of ER chaperones, characteristic of myodegenerative diseases such as s-IBM. Conversely, muscle regeneration and induction of ER stress markers were delayed in RNF5 KO mice subjected to cardiotoxin treatment. While supporting a role for RNF5 Tg mice as model for s-IBM, our study also establishes the importance of RNF5 in muscle physiology and its deregulation in ER stress associated muscular disorders

Segmental testicular infarction due to minocycline-induced antineutrophil cytoplasmic antibody-positive vasculitis

Segmental testicular infarction is an uncommon clinical entity marked by acute scrotal pain and swelling. Classically, these appear as wedge-shaped, avascular, hypoechoic lesions on a testicular ultrasound. We present a unique case of testicular infarct caused by an antineutrophil cytoplasmic antibody-positive vasculitis secondary to the use of the antibiotic minocycline. The patient\u27s symptoms resolved with cessation of minocycline. We suggest that patients who present with otherwise unexplained testicular infarction undergo a careful review of medications to uncover a potential cause. © 2014 Elsevier Inc

Resolution of Hydronephrosis and Pain to Predict Stone Passage for Patients With Acute Renal Colic

OBJECTIVE: To study patients who presented to the Emergency Department with acute renal colic to determine if resolution of hydronephrosis and pain accurately predicts stone passage on follow-up CT. MATERIALS AND METHODS: This is a secondary analysis of a multicenter prospective randomized clinical trial of patients diagnosed by computed tomography (CT) scan with a symptomatic ureteral stone \u3c 9 mm in diameter. Participants were followed after randomization to evaluate for analgesic use and to assess stone passage and hydronephrosis on a repeat CT scan obtained at 29-36 days. RESULTS: Four-hundred-three patients were randomized in the original study and patients were included in this analysis if they did not have surgery for stone removal and had a CT scan and information on pain medication at follow-up (N = 220). Hydronephrosis was detected in 181 (82%) on initial CT. At follow-up CT, 43 (20%) participants had a persistent ureteral stone. Of these patients, 36 (84%) had no pain, 26 (60%) did not have hydronephrosis, and 23 (53%) had neither pain nor hydronephrosis. Resolution of hydronephrosis was associated with stone passage (RR 4.6, 95% CI 1.9, 11.0), while resolution of pain was not (RR 1.1, 95% CI 0.9, 1.4). CONCLUSION: In patients with urinary stone disease, stone passage is associated with resolution of hydronephrosis but not resolution of pain. In patients with persistent ureteral stones, neither pain nor hydronephrosis are consistently present. These findings have important implications on follow-up imaging of patients with urinary stone disease