Pediatric Microbial Keratitis With Overnight Orthokeratology in Russia.

OBJECTIVES: To estimate the incidence of microbial keratitis in children wearing overnight orthokeratology lenses in Moscow, Russia. METHODS: To estimate the number of children wearing overnight orthokeratology lenses in 2018, 1,368 patient records from 13 Doctors Lens clinics were selected at random and extrapolated to the entire patient base. To identify cases of microbial keratitis, all episodes of infiltrative keratitis from Morozovskaya City Children's Clinical Hospital in 2018 were recorded and adjudicated by three experienced ophthalmologists. Incidence was calculated as the number of cases divided by the estimated number of wearers. RESULTS: There were 23,049 overnight orthokeratology fits between 2010 and 2018. Among the 1,368 records surveyed, 1,078 (79%) were younger than 18 years at initial fitting. Based on a 7% or 10% annual discontinuation rate, the estimated number of children wearing lenses in 2018 was 10,307 or 9,422, respectively. During 2018, there were 139 cases of corneal infiltrative keratitis in children and 45 were adjudicated as microbial keratitis (32%). Of these, 20 cases were associated with contact lens wear (44%): 15 soft lens wearers (33%) and 5 overnight orthokeratology wearers (11%). Based on the 5 cases and assuming a 7% or 10% discontinuation rate, the annual incidence is 4.9 (95% confidence interval[CI]: 2.1-11.4) or 5.3 (95% CI: 2.3-12.4) per 10,000 patient years. CONCLUSION: The incidence of microbial keratitis in children wearing overnight orthokeratology is lower than a previous United States study and similar to rates associated with use of daily wear soft contact lenses.

Turing patterns and long-time behavior in a three-species food-chain model.

We consider a spatially explicit three-species food chain model, describing generalist top predator-specialist middle predator-prey dynamics. We investigate the long-time dynamics of the model and show the existence of a finite dimensional global attractor in the product space, L(2)(Ω). We perform linear stability analysis and show that the model exhibits the phenomenon of Turing instability, as well as diffusion induced chaos. Various Turing patterns such as stripe patterns, mesh patterns, spot patterns, labyrinth patterns and weaving patterns are obtained, via numerical simulations in 1d as well as in 2d. The Turing and non-Turing space, in terms of model parameters, is also explored. Finally, we use methods from nonlinear time series analysis to reconstruct a low dimensional chaotic attractor of the model, and estimate its fractal dimension. This provides a lower bound, for the fractal dimension of the attractor, of the spatially explicit model.

Model for shock wave chaos.

We propose the following model equation, u(t) + 1/2(u(2)-uu(s))x = f(x,u(s)) that predicts chaotic shock waves, similar to those in detonations in chemically reacting mixtures. The equation is given on the half line, x<0, and the shock is located at x = 0 for any t ≥ 0. Here, u(s)(t) is the shock state and the source term f is taken to mimic the chemical energy release in detonations. This equation retains the essential physics needed to reproduce many properties of detonations in gaseous reactive mixtures: steady traveling wave solutions, instability of such solutions, and the onset of chaos. Our model is the first (to our knowledge) to describe chaos in shock waves by a scalar first-order partial differential equation. The chaos arises in the equation thanks to an interplay between the nonlinearity of the inviscid Burgers equation and a novel forcing term that is nonlocal in nature and has deep physical roots in reactive Euler equations.

Stress responses to comparative handling procedures in sheep.

The objective of this study was to compare some husbandry procedures on the base of physiological stress parameters and evaluate the welfare status in sheep. Forty ewes were used as the study material. Measurements were taken during several routine husbandry procedures such as milking, shearing, weighing, loading and hoof care. Data regarding time spent for each application, as well as heart and respiratory rates were recorded during the applications. Blood samples were taken 15 min before and after each application and malondialdehyde (MDA), glutathione-peroxidase (GSH-Px), cortisol T(3) and T(4) parameters were measured. In addition, changes in the same parameters between pre- and post-application periods were evaluated. According to the results, machine milking caused less stress than hand milking. No significant difference was seen between shearing methods for hand shearer or clipper; however, both applications caused stress in animals. The results for weighing methods of animals demonstrated significant differences in cortisol, T(3) and T(4) values in favor of traditional method. Cortisol, T(3) and T(4) levels were significantly higher in manual loading compared with loading by ramp. Regarding hoof care, all the examined parameters differed in favor of modern method. On the other hand, significant differences were determined between the stress parameters regarding pre- and post-applications. All values differed for hand milking while no significant difference was observed in MDA and T(3) values in machine milking group. Parameters in weighing groups changed significantly. For loading process, GSH, cortisol, T(3) and T(4) values differed in both treatment groups. With regard to hoof care, parameters except T(4) in laying group differed significantly. An increase occurred in minute-based measurements of heart and respiratory rates parallel to physiological data. The number of the respiratory rates during the applications differed except for the shearing process. All the parameters displayed significant differences between groups in terms of heart rates. Time spent for each application also differed between groups. Time saved for milking, shearing, weighing, loading and hoof care was 3.23 min, 4.37 min, 1.71 min, 7.85 s and 1.55 min, respectively. These results appear to provide a tangible advantage of using new husbandry methods to the breeders. It was concluded that using new methods in sheep husbandry procedures provided advantages in terms of saving time and reducing labor, as well as improved conditions for welfare of animals. In addition, it facilitated the routine works and flock husbandry.

Oral magnesium prophylaxis provides spontaneous resumption of cardiac rhythm in patients undergoing cardiac surgery.

Evidence is growing that magnesium supplementation in patients undergoing cardiac surgery is beneficial, however the best administration route has not been established. Previously, we showed that intra-operative direct flush infusion of magnesium into the aortic root before reperfusion was effective. The present study compared pre-operative oral administration of magnesium for 10 days with intra-operative flush infusion of magnesium for spontaneous resumption of cardiac rhythm and ventricular fibrillation in patients undergoing cardiac surgery with cardiopulmonary bypass (CBP). The rate of spontaneous resumption of cardiac rhythm, the number of shocks required for defibrillation, the energy required for defibrillation and the occurrence of post-CPB ventricular tachyarrhythmias were not significantly different between the groups. Serum magnesium levels were minimally increased following administration of magnesium but were within the normal range at all times in both groups. Oral administration of magnesium might provide my oprotective effects during cardiac surgery, but larger trials with a greater statistical power need to be carried out in order to show this.

An alternative, less invasive approach to median sternotomy for cardiac operations in adults: right infra-axillary minithoracotomy.

We compared the use of right infra-axillary minithoracotomy and conventional median sternotomy in direct open-heart surgery in 59 adults undergoing elective surgery for mitral valve stenosis, mitral valve disease, atrial septal defect repair, left atrial myxoma excision or mitral and tricuspid valve disease. Patients were randomized to the infra-axillary minithoracotomy group (Group A; n = 29) or the median sternotomy group (Group B; n = 30). Post-operative outcomes (post-operative bleeding; cross-clamp time; length of hospital and intensive care unit stays; and post-operative blood transfusion and analgesic requirements) were recorded and compared; they were found to be significantly lower in Group A than Group B. We concluded that right infra-axillary minithoracotomy is less invasive and can be used safely in adults as an alternative approach to conventional median sternotomy for some cardiac operations. Further multicentre studies in adults are now needed.

Magnesium-flush infusion into the aortic root just before reperfusion reduces the requirement for internal defibrillation and early post-perfusion arrhythmias.

Pre- and post-operative administration of magnesium has beneficial effects on post-operative ischaemia and reperfusion arrhythmias, but few studies have examined whether intra-operatively administered magnesium can prevent the effects of intra-operative arrhythmias. The aim of this randomized, double-blind study was to compare the effects of intra-operative magnesium or placebo on intra-operative arrhythmias in patients undergoing coronary bypass grafting. Patients received a flush infusion of magnesium or placebo into the aortic root before cross-clamp removal. The results showed that rate of spontaneous resumption of a cardiac rhythm was significantly higher, and number of shocks for defibrillation, energy requirement for defibrillation and rate of intra-operative ventricular tachyarrhythmias were significantly lower in the magnesium group, compared with the placebo group. The differences in need for temporary pacing, and in serum magnesium levels, were not significant. Intra-operative administration of magnesium has beneficial effects on the outcome of surgery. Larger, multicentre clinical investigations should now be undertaken.

Influence of noise exposure on antioxidant system and TEOAEs in rabbits.

Noise exposure may cause hearing loss. The precise mechanism leading to cochlear damage in aco trauma is not known. Eight rabbits were used in this study. Transient evoked otoacoustic emissions (TEOAEs) were recorded in all animals and blood malondialdehyde (MDA) and glutathione (GSH) levels were determined. All rabbits were then exposed to 100 dB SPL broadband noise for 1 h. TEOAEs were recorded again and blood MDA and GSH levels determined following noise exposure. The reproducibility scores of the TEOAE measurements were found to be significantly lower (P < 0.01), whereas the amplitudes and signal-to-noise values of emissions decreased (P > 0.01) in rabbits exposed to noise. The TEOAE energies were poor at 4 kHz. During this threshold shift, GSH blood levels decreased and MDA levels increased,indicating that there is a close relationship between noise-induced hearing loss and the antioxidant system. These findings indicate that TEOAE recording is an excellent test for detecting effects of noise on hearing.

Clinical, biochemical and histochemical assessment of pretreatment with glucose-insulin-potassium for patients undergoing mitral valve replacement in the third and fourth functional groups of the New York Heart Association.

In this study, the potentially beneficial effects of preoperative treatment with glucose, insulin and potassium in a randomized series of 30 consecutive patients undergoing mitral valve replacement, who were in the third and fourth functional groups of the New York Heart Association scale, were investigated. Fifteen patients received glucose, insulin and potassium, and 15 patients received the same volume of normal saline. The characteristics of the groups did not differ. Papillary muscle-biopsy samples were obtained at the time of surgery and analysed for glycogen, both biochemically and histochemically. The clinical course of all patients was monitored closely during the first 24 hours after surgery. The patients receiving glucose, insulin and potassium had higher glycogen levels (43 +/- 13.54 micromol/g) (P < 0.001). In addition, they required less inotropic pharmacological support (scored by the Gradinac method), had fewer ventricular arrhythmias and exhibited improved haemodynamic indices: cardiac output increased (P < 0.025 to P < 0.005), while systemic vascular resistance decreased (P < 0.001). Pretreatment with glucose, insulin and potassium did not, however, affect the patients' postoperative wedge pressure and mortality. The results of this study suggest that glucose, insulin and potassium pretreatment may be beneficial in unfit patients undergoing mitral valve replacement.

The effects of methylprednisolone on complement, immunoglobulins and pulmonary neutrophil sequestration during cardiopulmonary bypass.

In this study, the authors administered high dose (30 mg/kg body weight i.v.) methylprednisolone before cardiopulmonary bypass to observe the effects on complement, immunoglobulins and pulmonary neutrophil sequestration. Fifty patients undergoing valve replacements were included in this study. Patients were divided into two groups: group I (20 patients) served as control and did not receive methylprednisolone, group II (30 patients) received methylprednisolone. Blood samples for complements (C3c and C4) were taken, before cardiopulmonary bypass, at 5, 10 and 30 min intervals from the end of cardiopulmonary bypass, after reversal of heparin with protamine infusion, and after skin closure. Blood samples for immunoglobulins were taken before cardiopulmonary bypass, 30 min after onset of cardiopulmonary bypass and after skin closure. After onset of cardiopulmonary bypass, all C3c and C4 levels decreased in both groups. There was a significant decrease in C4 levels at end of cardiopulmonary bypass and after protamine infusion in group I compared with group II (P < 0.05). C3c levels in group I decreased significantly compared with group II after 30 min of cardiopulmonary bypass and after protamine infusion (P < 0.05). All immunoglobulin (IgG, IgM, IgA) levels were decreased in both groups, but the decrease in IgG was statistically significant after skin closure in group I compared with group II (P < 0.05). Pulmonary neutrophil sequestration was higher in the control group compared with the methyl-prednisolone group (P < 0.05). In conclusion, methylprednisolone administration before cardiopulmonary bypass may prevent the harmful effects of complement activation, immunoglobulin denaturation and neutrophil sequestration in the pulmonary capillary system.

Measurement of troponin T to detect cardioprotective effect of trimetazidine during coronary artery bypass grafting.

BACKGROUND: The aim of the present study was to evaluate potential myocardial protection by trimetazidine by measurement of the cardiac marker protein troponin T (TnT) during coronary bypass operations. METHODS: We conducted a double-blind, placebo-controlled study on 30 randomized patients who had aorta-coronary artery bypass operations. The TMZ group was composed of 15 patients and the placebo group of 15 patients in New York Heart Association class III or IV. Pretreatment was started 3 weeks preoperatively with trimetazidine (60 mg orally per day) or the placebo. In the trimetazidine TMZ group, there were 2 women and 13 men with a mean age of 57.1+/-2.2 years and mean cross-clamp time of 44+/-1.8 minutes. In the placebo group, there were 5 women and 10 men with a mean age of 58.4+/-1.2 years and a mean cross-clamp time of 42+/-2.4 minutes. Serial blood samples were collected before and after the operation, and serum concentrations of cardiac TnT were measured. RESULTS: The preoperative serum concentration of TnT was 0 to 0.39 ng/mL in all patients. The mean TnT levels were measured 5 minutes after completion of cardiopulmonary bypass (1.5+/-0.3 ng/mL) and 12 (1.4+/-0.1 ng/mL), 24 (0.9+/-0.1 ng/mL), and 48 hours postoperatively (0.1+/-0.1 ng/mL) in the trimetazidine group. Troponin T levels in the placebo group measured at the same time periods were 4.4+/-0.4, 4.8+/-0.7, 2.8+/-0.4, and 0.7+/-0.1 ng/mL. In the trimetazidine group, TnT levels were significantly less than those of the placebo group (p < 0.001). The levels of TnT were tested by creatine kinase-MB levels of both groups. Mean cardiac index was evaluated in all patients preoperatively and postoperatively. There was no significant difference in perioperative hemodynamics (blood pressure and cardiac index) between groups. CONCLUSIONS: These results obtained by measurement of cardiac TnT suggested that pretreatment with trimetazidine reduces ischemic-reperfusion damage during coronary bypass operations but did not affect postoperative hemodynamics.

Legal blindness and employment in patients with juvenile-onset macular dystrophies or achromatopsia.

PURPOSE: The purpose of this study was to gain information about the employment status of legally blind patients. METHODS: Fifty-two patients with one of four juvenile-onset macular dystrophies or achromatopsia responded to questions about their employment histories and their psychological well-being. Results from the questionnaire were analyzed using z-tests for differences in proportions or t-tests for differences in means. RESULTS: Forty-eight percent of the patients reported that they were employed and 52% that they were not employed. The subgroup that was not employed had a significantly higher proportion of women than men, whereas the employed group had approximately equivalent proportions of men and women. The employed subgroup reported that their success at work was due to social support. This subgroup had significantly higher household incomes, was significantly less likely to collect disability-income benefits, had significantly higher educational levels, had significantly higher positive affect, and had significantly lower negative affect than the subgroup that was not employed. A logistic regression analysis indicated that education was the primary predictor of employment. CONCLUSION: Analysis supports the conclusion that it is beneficial for legally blind individuals to obtain an optimal level of education and receive suitable social support to facilitate their successful employment.

Investigation of malondialdehyde formation and antioxidant enzyme activity in stored blood.

In the present study, fresh blood obtained from six healthy adult male donors was investigated for erythrocyte malondialdehyde (MDA) formation and antioxidative enzyme activity. Plasma and erythrocyte membrane lipid peroxidation were measured by MDA formation. Erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels were determined in whole blood stored for transfusion purposes. Erythrocyte and plasma MDA levels increased significantly during the storage period from day 3 to day 19 and, after that, stayed unchanged. Erythrocyte MDA increased 100% on day 7 when compared to day 1. The GSH-Px activity significantly decreased after day 9 and SOD decreased after day 13. The reduction in enzyme activities continued until day 27. Our results showed significant alteration in erythrocyte membrane and plasma MDA formation and intracellular antioxidant enzyme status in whole blood used for transfusion. However, we do not know whether such alterations have clinical importances for the recipient.

Effects of aprotinin on plasma levels of neutrophil elastase and postoperative blood loss in cardiac surgery.

This study evaluated the effects of aprotinin on plasma levels of elastase, platelet count, fibrinogen levels and postoperative bleeding. Thirty cardiac surgery patients were randomly chosen for this study. The protease inhibitor aprotinin was given in high doses to 20 patients before and during cardiopulmonary bypass; 10 patients served as the control group. Mean patient age and body weight was similar in both groups. There were no significant inter-group differences in the total cardiopulmonary bypass and cross-clamp times. Mean (s.e.m.) elastase levels were significantly raised in the control group (161.9(2.57) micrograms/l) compared with the treated group (148.2(3.29) micrograms/l) at 30 min of cardiopulmonary bypass (P < 0.01) and rose even further at the end of cardiopulmonary bypass, after protamine infusion, and 24 h postoperatively (P < 0.001). Platelet counts decreased more in the control group (P < 0.001). Serum fibrinogen levels were significantly lower in the controls during and just after cardiopulmonary bypass (P < 0.01). Postoperative blood loss was significantly less in the aprotinin-treated patients (315(25) ml) compared with the controls (589(154) ml) (P < 0.05). Aprotinin appears to inhibit elastase release and decrease postoperative blood loss.

The factors effecting complement activation in open heart surgery.

The activation of the complement system was investigated in 10 patients with rheumatic valve disease having heart surgery. The C3c, C4, leukocyte count and polymorphonuclear neutrophil count were determined in the blood samples taken before anaesthesia, after anaesthesia, 10 minutes after protamine administration and after the closure of the skin incision. In addition, atrial blood samples were taken after the release of the cross-clamp and pulmonary neutrophil trapping was investigated. In this study C3c and C4 consumption was found to take place after 30 minutes of CPB (cardiopulmonary bypass) and 10 minutes after protamine administration; the affects of anaesthesia and heparin were not significant.

Human umbilical cord vein grafts for replacement of the superior vena cava.

We have used umbilical veins as experimental graft materials for superior vena cava replacement. The patency rate of these grafts in 25 laboratory animals was 96%; the mortality and graft thrombosis rate was 4%. Histopathologically, no evidence of rejection was detected in the graft material. These results suggest that umbilical veins are superior to other prosthetic materials as grafts in venous surgery.