Adverse ophthalmic reaction in poppers users: case series of 'poppers maculopathy'.

BACKGROUND: Poppers are a recreational substance of abuse belonging to the alkyl nitrite family of compounds. In the United Kingdom, where they are legal to purchase but illegal to sell for human consumption, 10% of the general population have tried them. They are considered low risk to physical and mental health. Two recent case series from France demonstrated foveal pathology in individuals associated with poppers use. METHOD: A case series of seven patients presenting to four hospitals in the United Kingdom with visual impairment and maculopathy associated with inhalation of poppers. RESULTS: All patients experienced visual symptoms associated with poppers use. The majority had impaired visual acuity, central scotomata, distortion, or phosphenes. Clinical signs on fundoscopy ranged from normal foveal appearance to yellow, dome-shaped lesions at the foveola. Spectral domain optical coherence tomography (SD-OCT) showed varying degrees of disruption of the presumed inner segment/outer segment (IS/OS) junction. DISCUSSION: Although poppers have been in use for several decades, in 2007, following legislative changes, there was a change in the most commonly used compound from isobutyl nitrite to isopropyl nitrite. There were no reports of 'poppers maculopathy' before this. Poppers maculopathy may be missed if patients are not directly questioned about their use. The disruption or loss of the presumed IS/OS junction on SD-OCT are a characteristic feature. Further study of maculopathy in poppers users is now needed. Raising public awareness of the ocular risks associated with their use may be necessary.

Small G-protein Rho is involved in the maintenance of cardiac myocyte morphology.

The use of small membrane-permeable sequences or protein transduction domains (PTDs) can facilitate the transport of proteins into many cell types. In preliminary studies with the application of three PTDs (penetratin, modified penetratin, and the HIV TAT transduction domains) to cardiac myocytes, we found that the TAT and penetratin sequences showed high efficiency of uptake and low toxicity. Rho has been previously shown to be an important regulator of cytoskeletal organization and morphology in other non-cardiac cell types. To evaluate a role for Rho in cardiac myocyte morphology, we used the TAT-PTD to deliver a RhoA-specific inhibitor, the C3 exoenzyme, to cultured cardiac myocytes. We showed that this incubation with TAT-C3 abolished the basal levels of RhoA activity, demonstrating the efficacy of this treatment. Incubation with TAT-C3 also altered cardiac myocyte morphology so that TAT-C3-treated cells produced multiple projections from the major cell body. This was accompanied by a statistically significant increase in cell size, albeit to a lesser extent than the changes accompanying exposure to the hypertrophic agent, endothelin-1. Furthermore, the change in size of TAT-C3-treated cells was not accompanied by the induction of atrial natriuretic factor (ANF) expression that accompanies the hypertrophy of cardiac myocytes. These results reveal a role for RhoA in the maintenance of normal myocyte morphology.

Strabismus surgery: adjustable sutures-good for all?

AIMS: The role of adjustable sutures in strabismus surgery has mainly been limited to conditions like dysthyroid restrictive myopathy, blow-out fractures of orbit, aberrant regeneration of nerves, and certain other long-standing and complicated squints. In this clinical study, an attempt has been made to analyse the efficacy of adjustable sutures in squint surgery as a routine procedure. We also studied patients' acceptability and satisfaction following this procedure and analysed various factors that may influence the surgical outcome (age, sex, previous surgeries, injections of botulinum toxin, etc). METHODS: A total number of 443 patients, aged between 13 and 78 years, who underwent strabismus surgery in our department, from January 1996 to January 2000, were included in this study. Of these patients, 141 had surgery with adjustable sutures and 302 patients without adjustable sutures. Surgical results were followed up for a period ranging from 12 to 50 months. The main outcome measure was a need for a reoperation in the two groups. In addition, we also studied patients' satisfaction with regard to final cosmetic appearance or relief of diplopia; percentage change in angle of deviation in two groups, and influence of various factors such as age, sex, previous surgeries, and injection of botulinum toxin on the final surgical outcome. The results were statistically analysed using Levene's test for equality of variances, t-test for equality of means, and statistical significance of the results was analysed by calculating P-values. RESULTS: In total, 8.51% of the patients in the adjustable group and 27.15% in the nonadjustable group needed a reoperation. Surgical results were found to be significantly better in patients who had adjustable sutures in comparison to those who did not have adjustable sutures (P<0.005). Patients' satisfaction and percentage change in angle of deviation was also much higher in adjustable sutures group. Age, sex, number of previous surgeries, previous injections of botulinum toxin, and type and amount of deviation had no statistically significant influence on the surgical outcome. CONCLUSIONS: Strabismus surgery with adjustable sutures has a statistically significant better, final result than surgery without adjustable sutures. Patients' satisfaction and percentage change in angle of deviation is also much higher in the adjustable sutures group. As age, sex, number of previous surgeries, previous injections of botulinum toxin, and type and amount of deviation do not influence the final outcome, this type of surgery can be performed in virtually all types of patients.

Evaluation of the Pneupac Ventipac portable ventilator in critically ill patients.

We assessed adequacy of ventilation in 20 critically ill patients with multiple organ failure using a Pneupac Ventipac portable ventilator and the effects on patients' haemodynamic stability. Baseline data were recorded over 15 min for a range of respiratory, haemodynamic and oxygen transport variables during ventilation with a standard intensive care ventilator (Engström Erica). Patients were then ventilated for 40 min using the portable ventilator. Finally, they were ventilated for a further 40 min using the standard intensive care ventilator. Heart rate, arterial and pulmonary artery pressures were recorded at 5-min intervals throughout the study period. Cardiac index and other haemodynamic data derived from a pulmonary artery catheter were recorded at 20-min intervals. Blood gas analysis was performed and oxygen transport data (oxygen delivery, oxygen consumption and physiological shunt) were calculated at the end of each of the three periods of ventilation. In general, no significant adverse effects of ventilation using the portable ventilator were observed for any of the variables studied. Arterial PO(2) increased significantly during ventilation with the portable ventilator, reflecting the use of a higher inspired oxygen fraction during this part of the study. Oxygen consumption decreased significantly in one patient during ventilation by the portable ventilator although none of the other variables measured in this patient was altered. We conclude that ventilation of critically ill patients using the Pneupac Ventipac portable ventilator was safe, satisfactory and associated with minimal adverse effects on respiratory, haemodynamic and oxygen transport variables.

Inter-observer agreement in clinical optic disc measurement using a modified 60 D lens.

PURPOSE: To assess the inter-observer agreement of the measurement of optic disc dimensions by two observers using a modified 60 dioptre (D) fundus examination lens. METHOD: The vertical disc and cup diameters of 29 eyes were measured by two independent observers using a 60 D lens modified by incorporation of a 0.1 millimetre scale graticule. The vertical cup/disc ratio was calculated. Inter-observer agreement was assessed by calculation of the inter-observer differences and by the weighted kappa statistic. RESULTS: The two observers showed good agreement for the measurement of disc diameter (mean difference -0.04; range -0.04, 0.2) and for cup diameter (mean difference -0.03; range 0.3, 0.2). Closer agreement for the vertical cup/disc ratio was achieved (mean kappa 0.96; 95% confidence limits 0.90, 1.0). The 95% confidence limit for the mean inter-observer difference in cup/disc ratio was 0.11, suggesting that a change of > 0.1 in the assessment of the cup/disc ratio by this technique is significant at the 5% level. CONCLUSION: High inter-observer agreement of optic disc measurement can be achieved with this technique. The method has the potential to improve the clinical evaluation of the optic disc and the precision and accuracy of the clinical measurement of other fundal structures.

Axial length biometry in infants with retinopathy of prematurity.

Ultrasound axial length measurements were obtained on infants under a birthweight of 1500 g or 32 weeks gestation undergoing screening for retinopathy of prematurity (ROP). A total of 496 readings were obtained on 171 infants between 32 and 41 weeks post-conceptual age. Other details recorded were maximum stage of acute ROP, birthweight, gestational age, sex, and biparietal and occipitofrontal head diameters. The relationship of these variables to axial growth of the eye was examined using analysis of covariance with a repeated measures approach. Mean axial length increased from 15.27 mm to 16.65 mm in the left eye during this period. Following adjustment for repeated readings a growth rate of 0.18 mm/week was obtained for both eyes. Male infants were found to have longer axial lengths despite correction for birthweight, gestation and head size (p < 0.0001 right and left). Higher stages of acute ROP were also associated with shorter axial length (p < 0.05 for all stages of both eyes) but the rate of growth during the study period did not demonstrate significant differences between stages. Stage 3 infants reaching the threshold for cryotherapy had shorter axial length than stage 3 infants not receiving treatment. The effect of prematurity on the growth of the eye and the significance of these findings with respect to the subsequent development of refractive errors in premature infants are discussed.

Traumatic retinal angiopathy and seat belts: pathogenesis of whiplash injury.

Three cases of traumatic retinal angiopathy associated with whiplash injury are presented. The pathogenesis of the fundal appearances is discussed. Local microcirculatory disturbances are postulated as the cause of the retinopathy as opposed to the systemic disturbance associated with Purtscher's retinopathy. This condition may be underdiagnosed as there may be few abnormal signs on funduscopy. Fluorescein angiography may be very helpful. The incidence may be increasing as a result of legislation concerning the wearing of seat belts, and the condition has medico-legal significance. Increasing awareness may increase diagnosis.