Bilateral severe keratoconus after laser in situ keratomileusis in a patient with forme fruste keratoconus.

We report a case of bilateral keratoconus after laser in situ keratomileusis (LASIK). Before surgery, the patient had a forme fruste keratoconus, which evolved rapidly to a severe form of keratoconus in the months following LASIK. From this case, we conclude that forme fruste keratoconus is a contraindication to LASIK.

Inflammation is probably not a prerequisite for renal interstitial fibrosis in normoglycemic obese rats.

We examined the role of inflammation in the development of renal interstitial fibrosis in Zucker obese rats, which rapidly present kidney lesions in the absence of hypertension and hyperglycemia. Type I and III collagens were quantified using a polarized light and computer-assisted image analyzer. The expression of mRNA encoding matrix components, adhesion molecules, chemokines, and growth factors was followed by RT-PCR. The presence of synthesized proteins as well as lymphocytes and macrophages was determined by immunohistochemistry. Interstitial fibrosis developed in two phases. The first phase occurred as early as 3 mo and resulted from a neosynthesis of type III collagen and fibronectin and a reduction of extracellular matrix catabolism, in parallel with an overexpression of transforming growth factor-beta(1) and in the absence of any lymphocyte or macrophage infiltration. After 6 mo, interstitial fibrosis worsened with a large accumulation of type I collagen, concomitantly with a large macrophage infiltration. Thus inflammation cannot explain the onset of interstitial fibrosis that developed in young, insulinoresistant, normoglycemic, obese Zucker rats but aggravated this process afterward.

Cholesterol, a cell size-dependent signal that regulates glucose metabolism and gene expression in adipocytes.

Enlarged fat cells exhibit modified metabolic capacities, which could be involved in the metabolic complications of obesity at the whole body level. We show here that sterol regulatory element-binding protein 2 (SREBP-2) and its target genes are induced in the adipose tissue of several models of rodent obesity, suggesting cholesterol imbalance in enlarged adipocytes. Within a particular fat pad, larger adipocytes have reduced membrane cholesterol concentrations compared with smaller fat cells, demonstrating that altered cholesterol distribution is characteristic of adipocyte hypertrophy per se. We show that treatment with methyl-beta-cyclodextrin, which mimics the membrane cholesterol reduction of hypertrophied adipocytes, induces insulin resistance. We also produced cholesterol depletion by mevastatin treatment, which activates SREBP-2 and its target genes. The analysis of 40 adipocyte genes showed that the response to cholesterol depletion implicated genes involved in cholesterol traffic (caveolin 2, scavenger receptor BI, and ATP binding cassette 1 genes) but also adipocyte-derived secretion products (tumor necrosis factor alpha, angiotensinogen, and interleukin-6) and proteins involved in energy metabolism (fatty acid synthase, GLUT 4, and UCP3). These data demonstrate that altering cholesterol balance profoundly modifies adipocyte metabolism in a way resembling that seen in hypertrophied fat cells from obese rodents or humans. This is the first evidence that intracellular cholesterol might serve as a link between fat cell size and adipocyte metabolic activity.

The VF-14 index of functional visual impairment in candidates for a corneal graft.

PURPOSE: To validate the Visual Function-14 (VF-14) index of functional visual impairment in candidates for a corneal graft. METHODS: One hundred thirty-four patients who were candidates for a corneal graft participated in this study between August 1996 and February 1997. Demographic, ocular history, best-corrected visual acuity, and detailed ocular examination data were collected. Functional visual impairment information was obtained by telephone interviews using the following: VF-14, SF-36 (Short Form-36, a more generic measure of general health function), and Visual Symptom Score, and four questions measuring the overall amount of trouble with vision, dissatisfaction with vision, ocular pain, and discomfort. RESULTS: The average age of corneal graft candidates was 64 +/- 18 years (range, 18 to 90 years) and 60% were women. The most frequent corneal disease was pseudophakic bullous keratopathy (41%). Ocular comorbidities included glaucoma or ocular hypertension (30%) and cataract (19%). The mean best-corrected visual acuity of the eye scheduled for surgery was 1.33 +/- 0.56 logMAR whereas the best eye best-corrected visual acuity was 0.36 +/- 0.44 logMAR. The mean VF-14 score was 73% +/- 26%, and the internal consistency was high, with a Cronbach alpha value of 0.94. The VF-14 correlated strongly with the best eye best-corrected visual acuity. It also correlated strongly with the Visual Symptom Score, the global measures of trouble and dissatisfaction with vision. Candidates for a corneal graft had low scores for all eight general health concepts evaluated with the SF-36, and the VF-14 correlated with seven of the eight SF-36 subscales. CONCLUSION: The VF-14 is a valid measure of functional visual impairment in candidates for a corneal graft. The Visual Symptom Score and the SF-36 are also useful indices in such patients.

Evidence for the presence of several phosphodiesterase isoforms in brown adipose tissue of Zucker rats: modulation of PDE2 by the fa gene expression.

The present study was undertaken to characterise the phosphodiesterases (PDEs) present in brown adipose tissue (BAT) of Zucker rat pups and to determine whether the capacity for degradation of cyclic nucleotides was affected by the fatty genotype. Regardless of the genotype, PDE2-4 contributed to total PDE activity, the PDE3 activity equalling the sum of PDE2 and 4 activities. In fa/fa compared to Fa/fa rats, (a) PDE2 activity was significantly increased, (b) Western blot analysis of PDE2 revealed two signals at 71 and 105 kDa, with changes in protein being in good parallelism with changes in activity, (c) the PDE2 mRNA concentration was also significantly increased. In good agreement, the cGMP concentration was decreased in BAT from fa/fa pups.

Effects of triiodothyronine administration on the adenylyl cyclase system in brown adipose tissue of rat.

This study was undertaken to investigate the effect of triiodothyronine (T3) administration to euthyroid rats on beta 3-adrenoceptor (beta 3-AR) expression and on the different components of the adenylyl cyclase (AC) system in brown adipose tissue (BAT). In rats treated with T3, the beta 3-AR density (assessed by the binding of [3H]CGP-12177) showed a decrease of 50%, as did their mRNA, as analyzed by reverse transcriptase-polymerase chain reaction. In hyperthyroid rats, compared with control rats, there was a 40% increase in G alpha s activity (stimulated by NaF or GTP gamma S) and a fourfold increase in the protein concentration (Western blotting). In contrast, the level of the pertussis toxin substrate Gi declined by 35% in response to T3. Analysis of dose-response curves for isoproterenol and CGP-12177 revealed that neither basal nor stimulated AC activities nor 50% stimulatory concentration for these agonists was changed by T3 administration. In conclusion, these results suggest that downregulation of the beta 3-AR by T3 was counter-balanced by changes in other components of the AC cascade (i.e., Gs and Gi), so no change occurred in the capacity of BAT to generate adenosine 3',5'-cyclic monophosphate.

Role of ABO and Lewis blood group antigens in donor-recipient compatibility of corneal transplantation rejection.

PURPOSE: There are conflicting results regarding the role of human leukocyte antigen (HLA) matching and ABO compatibility in corneal graft rejection for low- and high-risk patients. Lewis blood group antigens could be an important histocompatibility system. Beneficial effects of Lewis antigens matching have been reported in renal transplantation, but its effect is still unknown in corneal allografting. METHODS: Between 1987 and 1993, ABO, Lewis and HLA phenotypes were determined in 697 consecutive grafts of corneal transplantations. The effect of Lewis matching on corneal endothelial rejection was evaluated over a 3-year period. Data analysis was done by plotting survival curves with the Kaplan-Meier method for survivorship data and performing statistical analysis with the log-rank test (Mantel-Haenszel test) for curve comparison. RESULTS: In vascularized recipients, the ABO, Lewis, and HLA systems did not influence the graft outcome. However, for the unvascularized recipients, the endothelial 3-year rejection rate was significantly lower for both Lewis compatible patients (84% vs. 68%; log rank = 0.03) and HLA compatible patients (86% vs 72%; log rank = 0.001), but not for the ABO-matched patients (82% vs. 79%; log rank = 0.56). CONCLUSIONS: The authors' study suggests that Lewis antigens and HLA matching could positively influence corneal graft survival for the unvascularized recipients, but it did not seem to have any effect in vascularized recipients.

Analysis of IgM structures involved in J chain incorporation.

J chain is associated with pentameric IgM and polymeric IgA. In IgM, J chain is disulfide bonded to the C575 residue of the mu-chain, located in the mu tail piece (mu tp). Previous studies indicated that mu tp is not sufficient to mediate J chain incorporation into polymeric Ig. In this study, we analyzed which other C mu domains are involved in J chain incorporation. Three altered forms of mouse IgM were analyzed: IgM lacking the C mu 1 domain, IgM in which the C mu 2 and C mu 3 domains were replaced by the hinge region and the C gamma 2 domain of IgG2b, and IgM, in which the C mu 4 domain was replaced by C gamma 3. We found that neither C mu 1, C mu 2, nor C mu 3 was absolutely required for J chain incorporation. The importance of C mu 4 could not be fully analyzed because the C gamma 3 replacement mutant failed to form polymers. Also, we found that the glycosylation site at asparagine 563 of mu tp was important for J chain incorporation. Disruption of this site by replacement of either asparagine 563 by tyrosine or serine 565 by phenylalanine resulted in diminished J chain incorporation and increased production of hexameric IgM. These results demonstrate the importance of structural elements located close to mu tp in the incorporation of J chain into IgM.

Early influx of glomerular macrophages precedes glomerulosclerosis in the obese Zucker rat model.

Because hyperlipidemia and macrophage influx appear to play a key role in the genesis of renal glomerulosclerosis, this study examined the temporal relationship between hyperlipidemia (triglycerides and cholesterol), mononuclear cell influx, changes in glomerular structure, and expansion of the extracellular matrices in obese Zucker rats, which rapidly develop hyperlipidemia and spontaneous glomerulosclerosis. Lean and obese Zucker rats were fed a standard diet, and were euthanized at 14 days, 1, 3, 6, 9, and 12 months. Plasma lipid, insulin, and creatinine levels were measured, and the presence of inflammatory cells in the glomerulus was assessed by immunohistochemistry on kidney sections. Plasma lipids and insulin and macrophage density were significantly greater in obese than in lean rats as early as 1 month. Computer-assisted image analysis was used to evaluate the glomerular domain surface areas. The morphometric measurements showed that glomeruli of obese rats rapidly became hypertrophied after 3 months, as a result of a very large increase in the mesangial domain. The expression of genes for extracellular matrix components and inhibitors of extracellular matrix proteinases (TIMP-1 and TIMP-2) was monitored in microdissected glomeruli. Reverse transcription-polymerase chain reaction showed increases in mRNA for Type IV collagen and fibronectin and for the two metalloproteinase inhibitors, each of which might participate in this matrix expansion. Thus, the development of hyperlipidemia plus macrophage influx at a very early age may initiate a sequence of events leading to glomerulosclerosis later on.

[Comparative efficacy of 0.1% indomethacin eyedrops, 0.03% flurbiprofen eyedrops and placebo for maintaining peroperative mydriasis]. / Efficacité comparée de l'indométacine collyre à 0.1%, du flurbiprofène collyre à 0.03% et d'un placebo sur le maintien de la mydriase peropératoire.

A randomized, double-blind study was conducted to compare the effect of 0.1% indomethacin solution versus 0.03% flurbiprofen versus placebo on the maintenance of mydriasis during cataract surgery. Ninety-five patients undergoing extracapsular cataract extraction with posterior chamber lens implantation were enrolled. Pupillary diameters were measured horizontally under operating-microscope visualization before 5 surgical steps: 1. corneo-scleral incision; 2. lens nucleus expression; 3. lens cortex material aspiration; 4. intra-ocular lens implantation; 5. end of surgery. The mydriasis loss during surgery was statistically less in the 2 groups treated by non steroidal anti-inflammatory drugs than in the placebo group. This effectiveness appeared at the time of lens nucleus expression (p = 0.0001) and persisted until the end of surgery. Then, the mydriasis was maintained during 2 crucial surgical steps requiring optimal pupillary dilation: lens cortex material aspiration and intra-ocular lens implantation. No significant difference was found between 0.1% indomethacin and 0.03% flurbiprofen concerning effectiveness and tolerance.

[Contribution of L lactate and amino-acid enzymatic biosensors for the analysis of Frey syndrome]. / Apport des biocapteurs enzymatiques à l lactate et à acide aminé pour l'analyse du syndrome de Frey.

Twelve patients with Frey's syndrome after total parotidectomy for plemorphic adenoma were analysed using simultaneously 2 biosensors. Biosensors allowed for detection of L lactate and amino acid level on intact skin. The assay procedure and the results achieved with the simultaneous use of these 2 biosensors are presented. The L lactate biosensor appears to be an interesting tool for Frey's syndrome analysis. The sensibility of the amino acid biosensor is not sufficient enough to allow its use at time of Frey's syndrome analysis.

Risk factors of corneal graft failure.

PURPOSE: To measure the association between potential risk factors and corneal graft failure. Two failure outcomes are compared: those with and those without a prior immune allograft reaction. METHODS: Based on a single-center observational study design, 539 adult recipients of a corneal graft were followed for a median time of 30 months. Survival analysis was carried out. RESULTS: Eighty-two graft failures were recorded. Of 82 failures, 53 (65%) were not preceded by an immune allograft reaction. Presence of blood vessels in the recipient cornea was associated with a twofold increase in risk for both failure outcomes. Three factors increased the risk of failure without an immune reaction: prior glaucoma or uveitis (adjusted relative risk estimate = 3.1), vitreous surgery with the graft (adjusted relative risk estimate = 2.0), and a repeat graft in the study eye (adjusted relative risk estimate = 2.0). Conversely, large graft wound size (adjusted relative risk estimate = 2.0). Conversely, large graft wound size (adjusted relative risk estimate = 2.9) and human leukocyte antigen (HLA)-A, -B incompatibility (adjusted relative risk estimate = 2.2) were associated with failures that followed an immune reaction. CONCLUSION: In this study, the authors support the clinical impression that corneal graft failures with and without a prior immune reaction are distinct phenomena. Enhanced surveillance in recipients with glaucoma and early intensive treatment of allograft reactions are recommended to improve the outcome of corneal grafts.

Frey's syndrome analysis with biosensor. A preliminary study.

OBJECTIVE: Objective quantification of Frey's syndrome (gustatory sweating), following total parotidectomy. A biosensoring method of enzymatic electrodes enabling the detection of L-lactate on intact skin with the use of a skin extraction device and enzymatic electrodes is presented and analyzed. DESIGN: A criterion standard study. SETTING: This prospective trial was undertaken at our research laboratory (University of Paris [France]). Parotidectomy was performed in our department, which is a tertiary care center for parotid gland pathology. PATIENTS: Twenty-eight patients with gustatory sweating following total parotidectomy and nine control patients not operated on were asked to take part in this prospective study. MAIN OUTCOME AND MEASURES: Gustatory sweating was assessed in all patients using a clinical scale, the Minor starch iodine test, and the L-lactate biosensoring method. RESULTS: Instrumentation and assay procedure for the L-lactate biosensoring method are detailed. Statistical analysis of data was performed using the Kruskal-Wallis H Test and the Mann-Whitney U Test. Results demonstrate that this method enables objective measurement of the L-lactate on skin without the need for chemical reagents, continuous nondestructive analysis in real time, and physiological dynamic monitoring of the L-lactate rate of production after stimulus. Data achieved strongly suggested that the aberrant regeneration theory is the main clue to Frey's syndrome pathogenesis. CONCLUSION: This safe, reliable, noninvasive, objective, and highly sensitive method provides an investigative tool for clinicians as well as physiologists involved with patients presenting gustatory sweating following parotid gland surgery.

Pretransplant and posttransplant antibodies in human corneal transplantation.

The purpose of this study was to measure the association between antibody formation and endothelial corneal allograft reactions in 533 consecutive corneal graft recipients. The median follow-up time of these recipients was 732 days. Pretransplant panel-reactive antibodies were not found to be associated with endothelial corneal allograft reactions. Out of 533 recipients, 239 developed posttransplant antibodies during the course of this study. The formation of posttransplant antibodies was frequent in recipients with pretransplant antibodies and in HLA-A,-B-incompatible recipients. Posttransplant antibodies most often appeared within the first six months after transplantation whereas endothelial allograft reactions most often occurred later. Out of 65 recipients who developed PPRA and underwent an allograft reaction, 53 had a PPRA peak prior to, or at about the time of, the allograft reaction. Corneal allograft reaction events diagnosed during the second and third year after surgery were correlated with PPRA formation during the first year after grafting. The 36-month reaction-free survival rate of transplants was estimated at 72% in recipients with PPRA compared with 86% in recipients without PPRA (log rank P value = 0.002). Furthermore, posttransplant antibody formation altered the outcome of corneal allografts in both HLA-A and -B-compatible and -incompatible recipients. These findings suggest that posttransplant antibody development represents a high risk of endothelial corneal allograft reactions.

CO2 laser annular thermokeratoplasty: a preliminary study.

Since most techniques of refractive surgery currently in use or being developed have the potential for significant side effects, there is a need for investigating alternative procedures. We herein report on the use of a pulsed CO2 laser beam delivered through a pair of complementary axicons to produce a ring of stromal collagen contraction resulting in the flattening of the corneal apex of cadaver eyes. Irradiances of 29 W/cm2 and 23 W/cm2 were used for rings of 5.5 mm and 7.0 mm, respectively. The creation of a ring of 7.0 mm in diameter did not affect the corneal curvature significantly but when the diameter was reduced to 5.5 mm, substantial flattening proportional to the dose of radiation took place. In our system, it was possible to achieve up to 11.3 diopters of mean keratometry flattening (90 joules, 5.5 mm of diameter). In addition, a 1 mm posterior displacement of the corneal dome without histological evidence of closure of the iridocorneal angle was observed. Annular thermokeratoplasty (ATK) may minimize side effects encountered with other refractive procedures since it does not require ablation, incisions, or interaction with the central optical zone.

Comparison of prednisolone acetate and indomethacin for maintaining mydriasis during cataract surgery.

Preoperative topical nonsteroidal anti-inflammatory drugs such as flurbiprofen and indomethacin have been found to maintain mydriasis during cataract surgery. Steroidal anti-inflammatory drugs are commonly used to treat postoperative inflammation, but their effect on the maintenance of intraoperative mydriasis is unknown. Forty-six patients admitted for elective cataract surgery were randomly assigned to one of three treatment groups and received 1% prednisolone acetate, 1% indomethacin or artificial tears four times before surgery, in addition to standardized preoperative dilating drops and intraoperative epinephrine. Pupillary diameter was measured and the time interval noted five times during the surgery. During surgery the indomethacin group lost significantly less mydriasis than the control group. The mydriasis losses of the prednisolone acetate group were between those of the indomethacin and control groups, but these differences did not reach significance. We conclude that prednisolone acetate is less effective than indomethacin for maintaining mydriasis during cataract surgery.

Increased proportion of B cell hybridomas secreting monoclonal antibodies of desired specificity in cultures containing macrophage-derived hybridoma growth factor (IL-6).

The addition of macrophage feeder cells or conditioned medium has been shown to increase the yield of murine hybridomas obtained after the fusion of myeloma cells and activated B lymphocytes. It has been shown recently that the conditioned medium contains a growth factor (HGF) active on newly formed hybridomas and that the human HGF is similar to B cell stimulatory factor 2 which can induce the synthesis of antibodies in transformed B cells. We have compared in several fusion experiments the stimulatory effects of HGF both on the yield of hybridomas and on the number of antibody-secreting hybridomas. The results obtained clearly showed that while the stimulatory effect of HGF on the yield of growth-positive wells was variable and sometimes barely detectable, the proportion of growth-positive wells containing monoclonal antibodies was consistently much higher in the HGF-containing cultures. These results suggest that the majority of the antibody-secreting newly formed hybridomas are sensitive to HGF and indicate that HGF is a very useful culture supplement for the generation of a high number of antibody-producing hybridomas even if it may not increase significantly the yield of viable hybridomas.