Identification of the major HOx radical pathways in an indoor air environment.

OH and HO2 profiles measured in a real environment have been compared to the results of the INCA-Indoor model to improve our understanding of indoor chemistry. Significant levels of both radicals have been measured and their profiles display similar diurnal behavior, reaching peak concentrations during direct sunlight (up to 1.6×106 and 4.0×107  cm-3 for OH and HO2 , respectively). Concentrations of O3 , NOx , volatile organic compounds (VOCs), HONO, and photolysis frequencies were constrained to the observed values. The HOx profiles are well simulated in terms of variation for both species (Pearson's coefficients: pOH =0.55, pHO2 =0.76) and concentration for OH (mean normalized bias error: MNBEOH =-30%), HO2 concentration being always underestimated (MNBEHO2 =-62%). Production and loss pathways analysis confirmed HONO photolysis role as an OH precursor (here up to 50% of the production rate). HO2 formation is linked to OH-initiated VOC oxidation. A sensitivity analysis was conducted by varying HONO, VOCs, and NO concentrations. OH, HO2 , and formaldehyde concentrations increase with HONO concentrations; OH and formaldehyde concentrations are weakly dependent on NO, whereas HO2 concentrations are strongly reduced with increasing NO. Increasing VOC concentrations decreases OH by consumption and enhances HO2 and formaldehyde.

Assessment of indoor HONO formation mechanisms based on in situ measurements and modeling.

The photolysis of HONO has been found to be the oxidation driver through OH formation in the indoor air measurement campaign SURFin, an extensive campaign carried out in July 2012 in a classroom in Marseille. In this study, the INCA-Indoor model is used to evaluate different HONO formation mechanisms that have been used previously in indoor air quality models. In order to avoid biases in the results due to the uncertainty in rate constants, those parameters were adjusted to fit one representative day of the SURFin campaign. Then, the mechanisms have been tested with the optimized parameters against other experiments carried out during the SURFin campaign. Based on the observations and these findings, we propose a new mechanism incorporating sorption of NO2 onto surfaces with possible saturation of these surfaces. This mechanism is able to better reproduce the experimental profiles over a large range of conditions.

Prospective randomized clinical trial on the effects of latanoprost, travoprost and bimatoprost on latanoprost non-responders.

PURPOSE: To determine whether a patient who is non-responder to latanoprost after one month of use should continue using latanoprost or switch to either bimatoprost or travoprost. PATIENTS AND METHODS: Prospective randomized clinical trial. We recruited new patients who were felt to require intraocular pressure reduction. Patients who had≤20% intraocular pressure reduction after one month of latanoprost treatment were randomly assigned to another month of treatment with latanoprost or a switch to bimatoprost or travoprost for an additional month. RESULTS: Overall, 83 non-responders to latanoprost after one month of treatment were included in the study. Before latanoprost treatment, the mean intraocular pressure was 23.7±4.7mmHg. At randomization on latanoprost, mean intraocular pressure was 21.5±4.5mmHg. One month after the switch of medication, the mean reduction in intraocular pressure was not significantly different between the groups (P=0.148) and was -0.9mmHg, -2.10mmHg and -2.5mmHg, for latanoprost, bimatoprost and travoprost respectively. One month after randomization, 32 (38.5%) of the patients had become responders, with IOP reduction>20%. Of those patients, 9 (31%) were using latanoprost, 13 (41.9%) bimatoprost and 10 (43.5%) travoprost. The number of new responders was similar between the three groups (P=0.584). CONCLUSION: There is no added benefit of switching latanoprost to another topical prostaglandin for patients who are initially non-responders. Regression towards the mean and the Hawthorne effect are probably important factors explaining the additional IOP reduction obtained after randomization and explain the result of most switch studies.

Reconstructive surgery of mitral valve incompetence: ten-year appraisal.

Between January, 1969, and January, 1978, 551 patients with mitral incompetence were treated by a system of reconstructive techniques. Mitral valve incompetence was classified into three types according to leaflet pliability; type I normal leaflet motion, 150 cases; type II, leaflet prolapse, 213 cases; and type III, restricted leaflet motion, 188 cases. Associated tricuspid valvular disease was present in 174 cases (31.5%) and was treated by prosthetic ring annuloplasty. The operative mortality rate was 4.2% (16/377) in the mitral group and 14% (25/174) in the mitral-tricuspid group. Follow-up data are available in 341 patients from 1 year to 10 years (average 4 1/2 years). The late mortality rate was 7% (24/341). Actuarial curves including hospital mortality rate show an 82% survival rate at 9 years in the mitral group and a 79% rate in the mitral-tricuspid group. Thirty-seven patients (11%) underwent reoperation mainly for residual (17) or recurrent (16) mitral incompetence. Thromboembolism occurred in 12 patients for an embolic rate of 0.6% per patient-year, even though 48% were not given anticoagulants. Acorrding to the New York Heart Association (N.Y.H.A.) classification, 76% (207/270) of the patients were in Class I, 19% (51/270) were in Class II, 4% (10/270) were in Class III, and 0.7% were in Class IV (2/270). Results of postoperative catheterization and angiocardiography are available in 52 patients. Comparison between the various groups shows that the best results were obtained in type II mitral incompetence, followed by type I and type III mitral incompetence. This experience demonstrates that predictable and stable long-term results have been achieved by techniques of valvular reconstruction with a low incidence of thromboembolism. Reproducibility of the techniques is a limiting factor which can be overcome by adequate training and progressive experience. Patient selection is based on the valvular disease rather than age, physical condition, or cause of valvular disease.

Congenital malformations of the mitral valve in children. Pathology and surgical treatment.

A systematic study of congenital mitral valve malformations was undertaken on a surgical basis in an attempt to develop techniques of valvular reconstruction adapted to the various lesions. Forty-seven children between the ages of 4 months and 12 years (average 6 years, 4 months) have been operated upon between January, 1970, and March, 1976. Valvular lesions were classified into four group: Group I, mitral insufficiency owing to valvular lesions: Group II mitral insufficiency with subvalvular lesions; Group III, mitral insufficiency and stenosis; Group IV, stenosis. Associated lesions (ventricular or atrial septal defects, coarctation, or aortic valve stenosis) were present in 31 patients (65 per cent) and were corrected during the same operation. Valve reconsruction was possible in 38 patients whereas valve replacement was necessary in 9 patients. In the valve repair group there were three operative deaths (8 per cent), no late deaths, one reoperation for residual ventricular septal defect, and one myocardial infarction. In the valve replacement group of 9 patients, there were three operative deaths, three late deaths, and one case of repeated embolization. Thirty-one of 38 patients in the valve repair group were classified into Functional Class I after the operation (86 per cent), 2 were in Class II, and one in Class III. Minimal or moderate regurgitation and cardiomegaly persisted in the majority of the patients. Pulmonary artery pressure significantly decreased, however, as demonstrated by postoperative catheterization in 17 patients.

Trabeculectomy vs thermosclerostomy. A randomized prospective clinical trial.

In a prospective randomized clinical trial we compared the efficacy and safety of trabeculectomy and thermosclerostomy for the treatment of open angle glaucoma. Forty-eight eyes was treated by trabeculectomy and 50 eyes were treated by thermosclerostomy. The mean follow-up period was 2.7 years. Thermosclerostomy lowered intraocular pressure about 3 mm Hg lower than trabeculectomy on the average. However, the percentage of eyes with pressures less than 22 mm Hg was not different for the two operations. The main difference between trabeculectomy and thermosclerostomy was the number of complications. Postoperative flat anterior chamber, decrease in visual acuity, cataract, hypotony, and thin bleb with late perforation or infection all occurred more frequently after thermosclerostomy. In conclusion, although trabeculectomy is slightly less effective than thermosclerostomy in lowering pressure, its relative freedom from complications make it is more desirable filtering operation.

Acute pressure elevation following panretinal photocoagulation.

Intraocular pressure increased in 17 of 18 eyes treated for diabetic retinopathy with argon laser panretinal photocoagulation. All eyes had open anterior chamber angles before treatment. Fifteen eyes, continued to have open angles when first examined after treatment. The pressure elevation in these eyes averaged about 10 mm Hg, was detected soon after laser treatment, and persisted for several hours. Outflow facility usually was reduced. Three eyes had closed angles and elevated pressures when first examined after treatment. I addition, in five eyes that initially had open angles, angle closure developed later. Thus, the pressure elevation after extensive retinal photocoagulation usually begins with an open angle mechanism, but later may be due to angle closure as well. The reason for the pressure rise with an open angle is unknown.

Ventricular septal defect associated with aortic valve incompetence: results of two surgical managements.

Aortic valve insufficiency with ventricular septal defect is usually treated by plication of the commissures. However, long-term deterioration is common. We propose a new technique that corrects the aortic annulus dilatation and the leaflet prolapse and reinforces the sinus of Valsalva. Two groups were compared: group I (29 patients) had plication of the prolapsed leaflet(s) and folding of the free edge; group II (26 patients) had triangular resection of the prolapse cusp, annuloplasty, and reinforcement of the aortic wall. The two groups were similar with regarding to preoperative clinical data. There was no perioperative mortality. Primary failure (aortic valve replacement) occurred in 8 patients in group I (28%) and in 2 patients in group II (8%). The rate of secondary failure was 31% in group I and 4% in group II. The actuarial rate of freedom from reoperation at 5 years is 55% in group I and 88% in group II (p less than 0.05). The late mortality was 6.5% in group I and 10.9% in group II (no difference). We conclude that aortic valve insufficiency with ventricular septal defect is a malformation of the aortic leaflets, the annulus, and the sinus of Valsalva, and that the proposed technique offers a better result than the usual methods in terms of residual aortic valve insufficiency.

A 10-year comparison of mitral valve replacement with Carpentier-Edwards and Hancock porcine bioprostheses.

Two hundred fifty-three patients who underwent isolated mitral valve replacement with a porcine bioprosthesis had long-term evaluation. One hundred forty-seven patients received a Carpentier-Edwards porcine bioprosthesis and 106, a Hancock valve. There were no significant differences in preoperative clinical characteristics between the two groups. Cumulative follow-up was 1,375 patient-years. At 10 years, 93% +/- 2.5% of the patients in the Carpentier-Edwards group and 85% +/- 7.8% of those in the Hancock group were free from valve-related death (not significant), and 95% +/- 2% and 91% +/- 3.8%, respectively, were free from thromboembolism (not significant). At 10 years, 65% +/- 7.2% of the patients in the Carpentier-Edwards group and 66% +/- 7.2% of those in the Hancock group were free from structural valve deterioration (not significant), and 64% +/- 6% and 59% +/- 7.3%, respectively, were free from reoperation (not significant). We conclude that the first generation of Carpentier-Edwards and Hancock prostheses produce comparable long-term results in the mitral position.

Conservative management of the prolapsed mitral valve.

Prolapsed leaflet is the result of ruptured chordae, elongated chordae, or ruptured papillary muscle. Various techniques adapted to each of these lesions were developed, and repair of 213 prolapsed mitral valves was performed between 1969 and 1977. There were 109 patients with ruptured chordae treated by quadrangular resection of the prolapsed leaflet; 103 patients with elongated chordae were treated by either a "sliding plasty" of the papillary muscle or a "shortening plasty" of the chordae; and 1 patient with ruptured papillary muscle was treated by reimplantation. The great majority of patients had an associated annular dilatation or deformation requiring the use of a Carpentier ring to remodel the annulus and reinforce the repair. The operative mortality was 4% and the late mortality, 3%. There were 6 reoperations, 3 of which occurred within 1 year. Thromboembolic complications occurred in only 1 patient (0.5%), even though the majority of patients received no anticoagulation treatment. Actuarial curves demonstrated a 91% survival at 8 years.

Clinical evaluation of the Dicon CAT 100 applanation tonometer.

A comparison of the Dicon CAT 100 applanation tonometer with the Goldmann tonometer in anesthetized human eyes with normal corneas disclosed high correlations for low, intermediate, high, and mean readings, but regression analysis showed that the y intercept was significantly different from 0 and that the slope was different from 1. The CAT 100 systematically overestimated low intraocular pressure levels and underestimated high intraocular pressure levels and thus is not accurate enough for clinical use.

Long-term results of low power, long duration laser trabeculoplasty.

We performed argon laser trabeculoplasty using 0.2-second duration on 15 patients with primary open-angle glaucoma. We then retrospectively compared the results to a similar group of 14 patients on whom a duration of 0.1 second was used. Power was titrated to achieve blanching or small bubble formation. All the other treatment variables were kept constant. Before treatment, the two groups did not differ in mean age, visual acuity, intraocular pressure, or number of drugs. After treatment, there was a 7 to 8 mm Hg decrease in intraocular pressure for both groups over a two-year follow-up period. No statistically significant difference between the two groups was observed for intraocular pressure, visual acuity, or drug score at the various follow-up periods. No patient required subsequent filtering surgery.

Accuracy of Goldmann tonometry after refractive surgery.

PURPOSE: To assess the accuracy of Goldmann tonometry after refractive surgery. SETTING: Refractive surgery center, Sherbrooke, Quebec, Canada. METHODS: The charts of 824 patients who had radial keratotomy (RK) and 415 who had photorefractive keratectomy (PRK) by the same surgeon were retrospectively reviewed. Of these, 306 RK and 168 PRK patients had discontinued steroid use for at least 4 weeks postoperatively and were thus eligible for evaluation of preoperative and postoperative intraocular pressure (IOP). Only one eye per patient was used for statistical analysis. RESULTS: Preoperative data showed that age, mean keratometry, and pachymetry were related to IOP measurement with the Goldmann tonometer. Pachymetry was related to age and mean keratometry. The mean decrease in measured IOP after RK was 1.0 mm Hg +/- 3.21 (SD) (P < .05). The only positive correlation was with the number of incisions. The mean decrease in measured PRK was 2.4 +/- 3.02 mm Hg (P < .05). Men and older patients had a larger drop in IOP measurements. There was no correlation with any corneal or operative parameter. CONCLUSION: Refractive surgery changed the accuracy of the Goldmann tonometer, causing it to underestimate IOP. The change was more marked in older men who had PRK.

Intraocular pressure change measured by Goldmann tonometry after laser in situ keratomileusis.

PURPOSE: To assess the accuracy of Goldmann tonometry after laser in situ keratomileusis (LASIK). SETTING: University-based refractive surgery group (Clinique du Laser Visuel). METHOD: The database of patients who had LASIK was retrospectively reviewed. Preoperative and postoperative intraocular pressure (IOP) was measured in 145 patients. The correlation between decrease in IOP and various preoperative and intraoperative parameters was evaluated by regression analysis. Only one eye in patients having bilateral surgery was used for statistical analysis. RESULTS: Laser in situ keratomileusis was associated with a mean decrease in IOP of 1.9 mm Hg +/- 2.9 (SD). There was no significant correlation between the decrease and any parameter evaluated. CONCLUSION: Intraocular pressure after LASIK decreased by a mean of 1.9 +/- 2.9 mm Hg. The cause of the decrease remains unknown.

Diurnal variation of episcleral venous pressure in healthy patients: a pilot study.

PURPOSE: To study diurnal episcleral venous pressure (EVP) and its relation to intraocular pressure (IOP) in healthy patients. The influences of supine position and lid closure on EVP were also studied. DESIGN: Experimental observational study. PARTICIPANTS AND METHODS: Twelve healthy patients with no eye disease had their IOP and EVP measured at 16h00, 22h00, 22h30, 06h00, 06h30, 09h00, 12h00, and 16h00. Measurements at 22h30, 06h00, and 06h30 were performed on supine patients, and the measurement at 06h00 was with the eye that had been closed for the whole night. In a second experiment, EVP was measured on patients who were lying supine from 22h30 to 16h00 with one eye closed during the day. MAIN OUTCOME MEASURES: Episcleral venous pressure and IOP at varying time points during a 24-hour period. RESULTS: Episcleral venous pressure was relatively constant throughout the day except for a slight reduction at 22h00. After lying down, the EVP increased by 3.6 mm Hg and remained increased as long as the patient remained in this position. Eyelid closure did not affect EVP. IOP measured with the Tono-Pen closely followed the variations in EVP. CONCLUSION: Episcleral venous pressure remains relatively constant throughout the day. It increases in the supine position with a corresponding increase in IOP. Lid closure does not influence EVP or IOP.

Pattern electroretinogram and optic nerve section in pigeons.

We studied the effect of optic nerve section on the pattern electroretinogram (PERG) of 10 pigeons. Base line PERG and flash ERG were measured prior to surgery and then one optic nerve was cut. We measured PERG at various time intervals up to 24 weeks after the section. There was a sharp drop in PERG amplitude immediately following the section. It gradually returned to normal levels in the following 24 weeks. Significant decreases in time to peak were noted at 1 and 16 weeks for 0.5 cycle per degree checks and at 1, 2 and 9 weeks for 0.25 cycle per degree checks. The ERG generated by a TV stimulus did not change in amplitude but had a shorter time to peak at 24 weeks for a high intensity stimulus and at 16, 18, 24 weeks for a low intensity stimulus. Light and electron microscopic sections (at 24 weeks) revealed an almost complete loss of nerve fibers in the optic nerve. Retinal sections revealed only a few surviving ganglion cells and a few nerve fibers. This suggests that in pigeons, PERG is not generated by ganglion cells.

Surgery for aortic dissection: 53 operated cases with 32 in the acute phase.

53 cases of aortic dissections were operated on between 1961 and 1975 in the Service of Cardiovascular Surgery at the Broussais Hospital, Paris (Prof. Ch. Dubost). The present study deals with 32 cases operated on in the acute phase. 31 originated in the ascending aorta and 1 in the descending aorta. Operative mortality was 50% (16/32), 4 patients died immediately following sternotomy. Operation consisted in replacement of the ascending aorta for the majority of type I and II dissections. When aortic insufficiency was present, a simple resuspension procedure was effective in 50% of cases. The authors prefer early operative intervention in type I and II dissections and medical treatment in type III dissections.

Traumatic ventricular septal defects. Report of 3 cases with tricuspid valve rupture in 2 cases.

Traumatic ventricular septal defects (TVSD) are rare complications of cardiac trauma. This report describes 3 cases of TVSD secondary to penetrating trauma in 2 patients and to blunt trauma in one case. Echocardiography confirmed the diagnosis in all cases. Surgical correction was performed in the 3 cases. In 2 patients associated tricuspid trauma was present requiring tricuspid valve repair.

Traumatic rupture of the thoracic aorta with reference to 34 operated cases.

34 cases of traumatic rupture of the aortic isthmus have been operated on since 1963: 14 acute ruptures and 20 secondary false aneurysms. Diagnosis was confirmed by aortography. A special feature seen in cases of total transsection is described. Partial extracorporeal bypass was used in 29 cases and direct cross-clamping in 5 cases. Two techniques were used: direct end-to-end anastomosis in 9 patients and Dacron graft interposition in 25 cases. Primary end-to-end anastomosis more often was used in cases of early operation and partial rupture. Hospital mortality was 2 patients in the group of acute ruptures and 0 patient in chronic false aneurysm group. It was related to brain damage or sequelae of prolonged shock. Post-operative course was uneventful but 4 cases of respiratory failure and 4 cases of neurologic disturbances (2 brain dysfunctions and 2 spinal cord dysfunctions). These complications were transient and the patients recovered without sequelae. Clinical results have been recently appreciated in every long-term survivor (mean follow-up: 5 years) and are excellent. Angiographic controls undergone in 10 patients have shown no abnormalities.

Sodium hyaluronate in trabeculectomy: a retrospective study.

In this retrospective study the results of trabeculectomy in 21 patients with open-angle glaucoma and no previous eye surgery who were followed up for at least 1 year were analysed. In 10 patients sodium hyaluronate had been injected during the operation to cushion the anterior chamber; the other 11 patients served as controls. The two groups had been comparable preoperatively with respect to characteristics assessed postoperatively. The subjects in the sodium hyaluronate group had better visual acuity and less postoperative hypotony. Although the series was too small to statistically validate the following observations, these subjects had better visual fields, their intraocular pressure was easier to control, and they had fewer complications; in particular, none had collapse of the anterior chamber.