Comparison of Different Nutritional and Lifestyle Factors between Glaucoma Patients and an Age-Matched Normal Population

PURPOSE

To compare nutritional and lifestyle factors between glaucoma patients and an age-matched control group.

METHODS

One hundred and ninety (190) glaucoma patients were enrolled in this study. The control group comprised 97 age-matched participants. Data on physical activity, nicotine smoking, and several nutritional habits like coffee and alcohol consumption as well as high-salt and high-protein intake were collected using a standardised questionnaire.

RESULTS

Age and gender were not statistically significantly different between the groups. There was a tendency for higher physical activity in the glaucoma group in comparison to the control group (47.3 vs. 35.4%; p = 0.056). Statistically significantly more glaucoma patients were nonsmokers (n = 169; 89.4%) compared to the control group (n = 64; 66.7%; p = 0.001). Glaucoma patients were also more often teetotal compared to the control group (21.6% compared to 14.4%; p < 0.001). Similarly, more glaucoma patients drank larger amounts of coffee in comparison to the control group (p = 0.001). One hundred and seventy-six (96.7%) glaucoma patients and 88 (90.7%) control subjects had high-protein intake (p = 0.035). High-salt intake was significantly lower in the glaucoma group (69.3 vs. 73.2%; p = 0.018). Of the 190 glaucoma patients, 81 had early visual field impairments (MD > - 6 dB) and 109 patients had moderate (MD between - 6 dB and - 12 dB) to severe (MD < - 12 dB) visual field defects. The severity of visual field defects, whether early, moderate, or severe, had no statistically significant impact on lifestyle parameters.

CONCLUSION

Contrary to our original hypothesis that glaucoma patients would tend to follow an unhealthier lifestyle than the control group, the opposite was seen. Presumably, the cause of this healthier lifestyle is the desire to contribute positively through the course of the disease.

Repeatability and reproducibility of corneal deformation response parameters of dynamic ultra-high-speed Scheimpflug imaging in keratoconus

PURPOSE

To assess the repeatability and reproducibility of dynamic corneal response (DCR) parameters obtained by ultra-high-speed Scheimpflug imaging (Corvis ST); in keratoconic patients.

SETTING

Clinics in Germany, Italy, and Brazil.

DESIGN

Prospective, observational study.

METHODS

Patients were examined 3 times using 2 different dynamic Scheimpflug analyzers (Corvis ST) to obtain repeatability and reproducibility. The reliability of intraocular pressure (IOP), biomechanically corrected IOP (bIOP), pachymetry, and DCR parameters were assessed by the coefficient of repeatability, coefficient of variation (CoV), intraclass correlation coefficient (ICC), and within-subject standard deviation (sw).

RESULTS

Ninety-eight eyes from 98 KC patients were included. The sw of the IOP and bIOP did not exceed 1.1 mm Hg. A CoV less than 10% was found in all DCR parameters and had a good to excellent accordance regarding the ICC. The Corvis Biomechanical Index showed an excellent repeatability and interdevice reproducibility of 0.918 and 0.827, respectively. Also, the tomographic biomechanical index showed an excellent repeatability of 3 Corvis ST and Pentacam measurements (ICC = 0.997). With regard to keratoconic severity, a significant increase in the CoV was found between mild and moderate stages compared with the advanced stage. Nevertheless, it did not exceed 10% of the CoV in severe keratoconic eyes.

CONCLUSION

Corvis ST measurements in keratoconic eyes were highly repeatable and reproducible.

Scheimpflug Corneal Densitometry Changes After Trabeculectomy

PURPOSE

To study the possible changes in Scheimpflug corneal densitometry 6 months after mitomycin C-augmented trabeculectomy and to compare these measurements with healthy controls.

METHODS

Corneal densitometry was monitored with the Pentacam HR3 before and 6 months after first-time uncomplicated mitomycin C-augmented trabeculectomy in 42 eyes of 42 white patients with open-angle glaucoma and in 22 healthy age-matched controls. Preoperative intraocular pressure (IOP), central corneal thickness, known duration of the disease, gender, the type and number of substances, applications and amount of benzalkonium chloride per day, and postoperative topical cortisone use were tested for possible correlations in the trabeculectomy group.

RESULTS

There was a statistically significant reduction of mean diurnal IOP from 19.0 ± 7.7 to 11.1 ± 7.7 mm Hg (P = 0.003) and the amount of pressure-lowering substances from 3.7 ± 1.0 to 0.1 ± 0.5 (P < 0.001). Densitometry measurements decreased in the entire cornea from 25.5 ± 5.7 to 23.1 ± 5.8 grayscale units (P = 0.001) with emphasis in the anterior layer. They returned close to normal 6 months after trabeculectomy and were not statistically significantly different compared with a healthy control group (22.8 ± 3.4 grayscale unit; P = 0.824). No correlations could be found with these observations and possible causing factors studied.

CONCLUSIONS

Corneal densitometry, an objective and sensitive measure of corneal transparency, returned close to normal 6 months after trabeculectomy. Although the observations cannot be associated with any causing factor in this study, the significant IOP reduction and the nearly complete cessation of topical antiglaucomatous substances including benzalkonium chloride seem to be the most plausible reasons for this finding.

Comparison of waveform-derived corneal stiffness and stress-strain extensometry-derived corneal stiffness using different cross-linking irradiances: an experimental study with air-puff applanation of ex vivo porcine eyes

Purpose

To assess corneal stiffening of standard (S-CXL) and accelerated (A-CXL) cross-linking protocols by dynamic corneal response parameters and corneal bending stiffness (Kc[mean/linear]) derived from Corvis (CVS) Scheimpflug-based tonometry. These investigations were validated by corneal tensile stiffness (K[ts]), derived from stress-strain extensometry in ex vivo porcine eyes.

Methods

Seventy-two fresh-enucleated and de-epithelized porcine eyes were soaked in 0.1% riboflavin solution including 10% dextran for 10 min. The eyes were separated into four groups: controls (n = 18), S-CXL (intensity in mW/cm²*time in min; 3*30) (n = 18), A-CXL (9*10) (n = 18), and A-CXL (18*5) (n = 18), respectively. CXL was performed using CCL Vario. CVS measurements were performed on all eyes. Subsequently, corneal strips were extracted by a double-bladed scalpel and used for stress-strain measurements. K[ts] was calculated from a force-displacement curve. Mean corneal stiffness (Kc[mean]) and constant corneal stiffness (Kc[linear]) were calculated from raw CVS data.

Results

In CVS, biomechanical effects of cross-linking were shown to have a significantly decreased deflection amplitude as well as integrated radius, an increased IOP, and SP A1 (P < 0.05). Kc[mean]/Kc[linear] were significantly increased after CXL (P < 0.05). In the range from 2 to 6% strain, K[ts] was significantly higher in S-CXL (3*30) compared to A-CXL (9*10), A-CXL (18*5), and controls (P < 0.05). At 8% to 10% strain, all protocols induced a higher stiffness than controls (P < 0.05).

Conclusion

Several CVS parameters and Kc[mean] as well as Kc[linear] verify corneal stiffening effect after CXL on porcine eyes. S-CXL seems to have a higher tendency of stiffening than A-CXL protocols have, which was demonstrated by Scheimpflug-based tonometry and stress-strain extensometry.

Intraocular pressure measurements in diabetes mellitus

PURPOSE

To investigate the impact of diabetes mellitus-induced changes on intraocular pressure measurements using Goldmann applanation tonometry, Ocular Response Analyzer, and Corvis ST.

METHODS

Measurements were done using Goldmann applanation tonometry, Ocular Response Analyzer, and Corvis ST in 69 diabetic patients. Biomechanical-corrected intraocular pressure values by Ocular Response Analyzer (IOPcc) and Corvis ST (bIOP) were used. In addition, biometry and tomography were performed and information on diabetes mellitus specific factors was collected. Results were compared to an age-matched group of 68 healthy subjects.

RESULTS

In diabetes mellitus, Goldmann applanation tonometry intraocular pressure (P = 0.193) and central corneal thickness (P = 0.184) were slightly increased. Also, IOPcc (P = 0.075) and bIOP (P = 0.542) showed no significant group difference. In both groups, IOPcc was higher than Goldmann applanation tonometry intraocular pressure (P = 0.002, P < 0.001), while bIOP was nearly equal to Goldmann applanation tonometry intraocular pressure (P = 0.795, P = 0.323). Central corneal thickness showed a tendency to higher values in poorly controlled than in controlled diabetes mellitus (P = 0.059). Goldmann applanation tonometry intraocular pressure correlated to central corneal thickness, while IOPcc and bIOP were independent from central corneal thickness in both groups. All intraocular pressure values showed significant associations to corneal biomechanical parameters. Only in diabetes mellitus, bIOP was correlated to Pachy slope (P = 0.023).

CONCLUSION

In diabetes mellitus, Goldmann applanation tonometry intraocular pressure was slightly, but not significantly, increased, which might be caused by a higher central corneal thickness and changes in corneal biomechanical properties. However, intraocular pressure values measured by Ocular Response Analyzer and Corvis ST were not significantly different between diabetes mellitus patients and healthy subjects. The bIOP showed a higher agreement with Goldmann applanation tonometry than IOPcc and was independent from central corneal thickness.

A new biomechanical glaucoma factor to discriminate normal eyes from normal pressure glaucoma eyes

BACKGROUND

To test the ability of the newly calculated Dresden biomechanical glaucoma factor (DBGF) based on dynamic corneal response (DCR) deformation and corneal thickness parameters, to discriminate between healthy and normal pressure glaucoma (NPG) eyes.

METHODS

Seventy healthy and 70 NPG patients of Caucasian origin were recruited for this multicentre cross-sectional pilot study, which included both eyes for analysis. Logistic regression analysis with generalized estimating equation (GEE) models to account for correlations between eyes and a threefold cross-validation were performed to determine the optimal combination of Corvis ST parameters in order to separate normal from NPG eyes.

RESULTS

The DBGF was calculated using 5 Corvis ST parameters, which showed the best discrimination power: deformation amplitude ratio progression, highest concavity time, pachymetry slope, the biomechanically corrected intraocular pressure and pachymetry. In a threefold cross-validation, the receiver operating characteristic (ROC) curve confirmed an area under the curve (AUC) of 0.814 with a sensitivity of 76% and a specificity of 77% using a logit cut-off value of a DBGF = 0.5.

CONCLUSION

The DBGF shows to be sensitive and specific to discriminate healthy from NPG eyes. Since diagnosis of NPG is often challenging, the DBGF may help with the differential diagnosis of NPG in daily clinical practice. Therefore, it might be considered as a new possible screening method for NPG.

Clinical and visual outcome of endophthalmitis patients: a single-center experience

PURPOSE

To report the clinical and visual outcome and the therapeutical management in a large cohort of endophthalmitis patients.

METHODS

In a monocentric, observational study, we retrospectively analyzed the data of all patients with endophthalmitis who were referred to the department of ophthalmology of the Carl Gustav Carus Hospital Dresden between 2006 and 2018.

RESULTS

In total, data of 104 patients (49 female, 55 male) were included in the present analysis. The most frequent clinical scenario for endophthalmitis was postcataract surgery (30.8%). The most frequent treatment at presentation was a pars plana vitrectomy (ppV) in 42 patients, followed by an intravitreal antibiotic in 41 patients. Out of 41 patients who received an intravitreal antibiotic, 35 patients (85%) needed additional treatment. In contrast, out of 42 patients who received a ppV as the initial treatment, 19 patients (42%) needed additional therapy, which was significantly different (p < 0.0001). The best presenting visual acuity improved significantly after treatment (p < 0.0001).

CONCLUSION

The results of the present study suggest that, compared with an intravitreal antibiotic, a ppV as the initial therapy of endophthalmitis might reduce the number of additional treatments. From our data, it can be hypothesized that a ppV should be performed as early as possible to achieve the best visual outcome in most endophthalmitis patients. Prospective studies are now needed to address this issue in greater detail and to confirm our findings.

Influence of the beam profile crosslinking setting on changes in corneal topography and tomography in progressive keratoconus: Preliminary results

PURPOSE

To evaluate the effect of accelerated corneal crosslinking (CXL) with a "higher peripheral intensity" profile setting compared with a standard "top hat" profile setting performed using different CXL systems.

SETTING

Department of Ophthalmology, University Hospital Carl Gustav Carus, Dresden, Germany.

DESIGN

Retrospective case series.

METHODS

Eyes from patients with progressive keratoconus were included. Group 1 included eyes treated with the higher peripheral intensity profile. Group 2 included eyes treated with the top hat profile. Accelerated CXL was performed based on the modified Dresden protocol (9 mW/cm², 10 minutes). Corneal-topography and tomography are characterized using the Pentacam Scheimpflug system.

RESULTS

The study comprised 45 eyes (25 eyes in Group 1, 20 eyes in Group 2) from 45 patients. The keratometry (K) at the apex (maximum K) decreased significantly from 54.95 diopters (D) ± 6.73 (SD) to 53.21 ± 6.05 D for Group 1 (P < .001) and from 57.29 ± 7.16 D to 56.48 ± 6.88 D for Group 2 (P = .01). In Group 1, flat K (K1) and steep K (K2) decreased significantly after treatment (P < .05). The thinnest corneal thickness decreased significantly by -17.5 ± 21.9 μm (P = .001) in Group 1. In Group 2, no significant flattening was observed in K1 and K2 (P > .05), and the thinnest corneal thickness showed a slight but not significant thinning (P = .097).

CONCLUSIONS

In Group 1 (the higher peripheral intensity group), the corneal topographic and tomographic parameters improved significantly after accelerated CXL. The higher peripheral intensity profile effect on keratoconic cornea flattening seemed to be more pronounced compared with the top hat profile.

Measurement of Orbital Biomechanical Properties in Patients with Thyroid Orbitopathy Using the Dynamic Scheimpflug Analyzer (Corvis ST)

PURPOSE

To investigate orbital biomechanical properties in patients with thyroid orbitopathy and in age- and gender-matched healthy subjects using the Corvis-ST (CST, Oculus Wetzlar, Germany).

METHODS

The CST allows a non-contact tonometry with an ultra-high-speed Scheimpflug device to record the deformation of the cornea during an air pulse. Biomechanical response parameters (intraocular pressure (IOP), whole eye movement length (WEMl) and time (WEMt), deflection amplitude 2 mm ratio max, deflection amplitude max, stiffness parameter, and biomechanically corrected IOP were measured in 39 patients with thyroid orbitopathy (= group I) and in 33 age- and gender-matched healthy subjects (= group II) using the CST.

RESULTS

Mean age in group I was 54.3 ± 11.6 years and in group II 54.2 ± 12.3 years with no statistical significant difference between the groups (P = 0.98). The gender distribution between the groups was not statistically significantly different (P = 0.51). Mean central corneal thickness was 571 ± 30 µm in group I and 563 ± 36 µm in group II (P = 0.306). There were statistically significant differences (P < 0.001) between groups I and II in mean IOP (19.3 ± 4.5 vs. 14.8 ± 2.3 mmHg, mean biomechanically corrected IOP (17.1 ± 3.4 vs. 13.4 ± 2.1 mmHg), mean WEMl (207 ± 57 vs. 322 ± 50 µm), mean WEMt (20.5 ± 1.0 vs. 21.9 ± 0.7 ms), mean IOP-adjusted WEMl (213 ± 56 vs. 314 ± 62 µm), and in mean stiffness parameter (132.5 ± 29.6 vs. 107.8 ± 23.3 mmHg/mm), respectively.

CONCLUSION

Biomechanical parameters as measured by the CST were significantly reduced in patients with thyroid orbitopathy compared to age- and gender-matched healthy subjects, indicating a reduction in orbital compliance in thyroid orbitopathy. The parameters WEMl and WEMt might be a useful diagnostic tool to evaluate the condition of the eyeball within the orbit.

Keratokonus: heutige Therapieoptionen

Die Inzidenz des Keratokonus wird in aktuellen Studien deutlich höher geschätzt als bisher angenommen, somit wird diese Hornhautektasie nicht mehr zu den seltenen Erkrankungen gezählt. Als einer der bedeutendsten Risikofaktoren für die Entstehung des Keratokonus wurde neben Atopie und Down-Syndrom das chronische Augenreiben definiert. Dies ist der durch Verhaltenstraining und konsequente Aufklärung einzig wirklich modifizierbare Risikofaktor. Weitere Therapieoptionen beinhalten Maßnahmen zur Visusverbesserung wie die Anpassung von Brillen und formstabilen Kontaktlinsen, die Implantation kornealer Ringsegmente oder phaker intraokularer Linsen. Im Falle einer Krankheitsprogression bietet das korneale Crosslinking ein effektives und sicheres Verfahren, sodass das Erfordernis einer Hornhauttransplantation in dieser Indikation immer seltener wird. Neuere Studien sehen auch einen positiven Effekt einer Kombination der bisher bei Keratokonus kontraindizierten photorefraktiven Keratektomie und dem Crosslinking. Die perforierende Keratoplastik stellt allerdings weiterhin den Goldstandard der chirurgischen Behandlung des Keratokonus im fortgeschrittenen Stadium dar, wobei in den letzten Jahren auch die lamellären Verfahren immer mehr in den Vordergrund rücken.

Microseismological evidence for a changing wave climate in the northeast Atlantic Ocean

One possible consequence of a change in climate over the past several decades is an increase in wave heights, potentially threatening coastal areas as well as the marine industry. But the difficulties in observing wave heights exacerbates a general problem of climate-change detection: inhomogeneities in long-term observational records owing to changes in the instruments or techniques used, which may cause artificial trends. Ground movements with periods of 4-16 seconds, known as microseisms, are associated with ocean waves and coastal surf, and have been recorded continuously since the early days of seismology. Here we use such a 40-year record of wintertime microseisms from Hamburg, Germany, to reconstruct the wave climate in the northeast Atlantic Ocean. For the period 1954-77, we detect an average of seven days per month with strong microseismic activity, without a significant trend. This number increases significantly in the second half of the record, reaching approximately 14 days of strong microseisms per month. The implied increase in northeast Atlantic wave height over the past 20 years parallels increased surface air temperatures and storminess in this region, suggesting a common forcing.

Differential oxidation of apolipoprotein E isoforms and interaction with phospholipids

Accumulation of oxidized proteins has been demonstrated in the brain of patients suffering from Alzheimer's disease (AD). Among the proteins found in cerebral amyloid deposits, apolipoprotein (apo) E is a polymorphic protein which one specific isoform, apo E4, has been widely associated with AD. Apo E may be linked with AD by its isoform-specific interaction with lipids or other proteins in amyloid plaques. Using the myeloperoxidase oxidative system, we report that oxidation of the three recombinant apo E isoforms is differential (as estimated using immunoblot and high-performance liquid chromatography analysis), with apo E4 being more susceptible than apo E3, which in turn is much more susceptible than apo E2. In addition, susceptibility to thrombin proteolysis is reduced when apo E is oxidized, and oxidation of apo E decreases its incorporation into phospholipid discs by approximately 50%. Oxidation of apo E may contribute to inefficient lipid recycling in the brain, particularly regarding apo E4 and E3. Our results link and strengthen both the E4 allele linkage with AD and the role of protein oxidation in AD. The cerebral mechanisms underlying apo E oxidation and/or myeloperoxidase functions in vivo remain to be assessed.

Characterization of the UDP-glucuronosyltransferases involved in the glucuronidation of an antithrombotic thioxyloside in rat and humans

To investigate the glucuronidation on the hydroxyl group of carbohydrate-containing drugs, the in vitro formation of glucuronides on the thioxyloside ring of the antithrombotic drug, LF 4.0212, was followed in rat and human liver microsomes and with recombinant UDP-glucuronosyltransferases (UGT). The reaction revealed a marked regioselectivity in rat and humans. Human liver microsomes glucuronidated the compound mainly on the 2-hydroxyl position of the thioxyloside ring, whereas rat was able to form glucuronide on either the 2-, 3-, or 4- hydroxyl group of the molecule, although to a lower extent. LF 4.0212 was a much better substrate of human UGT than the rat enzyme (Vmax/Km 30.0 and 0.06 microl/min/mg, respectively). Phenobarbital, 3-methylcholanthrene, and clofibrate enhanced the glucuronidation of LF 4.0212 on positions 2, 3, and 4 of the thioxyloside ring, thus indicating that several UGT isoforms were involved in this process. The biosynthesis of the 2-O-glucuronide isomer was catalyzed by the human UGT1A9 and 2B4, but not by UGT1A6 and 2B11. By contrast, the rat liver recombinant UGT1A6 and 2B1 failed to form the 2-O-glucuronide isomers. From all the recombinant UGTs tested, none catalyzed the formation of the 3-O-glucuronide isomer. Interestingly, glucuronidation on the 4-position was found in all the metabolic competent V79 cell lines considered, including the nontransfected V79 cells, suggesting the presence of an endogenous UGT in fibroblasts able to actively glucuronidate the drug. This activity, which was nonsensitive to the inhibitory effect of 7,7,7-triphenylheptanoic acid, a potent UGT inhibitor, could reflect the existence of a different enzyme.

Species-dependent enantioselective glucuronidation of carprofen

1. The stereoselective glucuronidation of carprofen, a non-steroidal anti-inflammatory drug, was investigated in vitro using microsomes prepared from liver of different species (rat, dog, horse, sheep and man) or UGT2B1 expressed in fibroblasts. 2. The Km towards the drug was very similar among these species and for the two enantiomers, whereas the Vmax varied substantially according to the animal used. The rat exhibited a high stereoselective glucuronidation whereas other species, including man, presented a low stereoselectivity. The R-enantiomer was glucuronidated at a more efficient rate than its enantiomorph, and was a better substrate (in terms of Vmax/Km). 3. To explain the enantioselective disposition of carprofen in man and in the different species, the ratio of the enzymatic efficacies (Vmax/Km) were compared with the ratio of the pharmacokinetic parameters AUCs. The basic hypothesis that the intrinsic clearance reflect the enantioselective behaviour of carprofen seemed substantiated when we focused on man and rat glucuronidation, but the in vivo-in-vitro correlation was not possible in other species. 4. In conclusion, the chiral pharmacokinetics of carprofen is less dependent on the stereoselective glucuronidation than other stereoselective processes such as protein binding of carprofen, enzymatic hydrolysis, or renal elimination of glucuronides.

Effect of cigarette smoke on UDP-glucuronosyltransferase activity and cytochrome P450 content in liver, lung and kidney microsomes in mice

The effect of cigarette smoke on the expression of several cytochromes P450 (CYP) and UDP-glucuronosyl-transferases (UGT) was studied in mice. The animals were exposed to cigarette smoke for 4 to 30 days. Enzymatic activities supported by CYP1A1, 1A2, 2B, 2E1 and the glucuronidation activity toward phenols were measured in lung, liver and kidney microsomes. Cigarette smoke induced several CYPs, especially in lung. CYP2E1 was more induced than CYP1A1 in this organ. The expression of CYP2E1 was also increased in kidney (5.6 times after 30 days). The glucuronidation in kidney was non-sensitive to the treatment whatever substrate used. In contrast, this activity was enhanced in liver and particularly in lung, in which the glucuronidation of 1-naphthol and 2-hydroxybiphenyl was increased by 122 and 180%, respectively. Interestingly, the times of induction differed according to the substrate used, thus suggesting the presence of different UGTs active toward phenols that were differentially affected by cigarette smoke. The UGT activities toward phenols were low in lung, when compared with those measured in liver or kidney. In conclusion, cigarette smoke greatly affected both glucuronidation activity and the hydroxylation reactions supported by CYPs in mouse liver and lung.

Squamous epithelial hyperplasia and carcinoma in mice transgenic for the human papillomavirus type 16 E7 oncogene

The human papillomavirus type 16 (HPV-16) genome is commonly present in human cervical carcinoma, in which a subset of the viral genes, E6 and E7, are expressed. The HPV-16 E6 and E7 gene products can associated with and inactivate the tumor suppressor proteins p53 and Rb (the retinoblastoma susceptibility gene product), and in tissue culture cells, these viral genes display oncogenic properties. These findings have led to the hypothesis that E6 and E7 contribute to cervical carcinogenesis. This hypothesis has recently been tested by using transgenic mice as an animal model. HPV-16 E6 and E7 together were found to induce cancers in multiple tissues in which they were expressed, including squamous cell carcinoma, the cancer type most commonly associated with HPV-16 in the human cervix. We have extended these studies to investigate the in vivo activities of HPV-16 E7 when expressed in squamous epithelia of transgenic mice. Grossly, E7 transgenic mice had multiple phenotypes, including wrinkled skin that was apparent prior to the appearance of hair on neonates, thickened ears, and loss of hair in adults. In lines of mice expressing higher levels of E7, we observed stunted growth and mortality at an early age, potentially caused by an incapacity to feed. Histological analysis demonstrated that E7 causes epidermal hyperplasia in multiple transgenic lineages with high penetrance. This epithelial hyperplasia was characterized by an expansion of the proliferating compartment and an expansion of the keratin 10-positive layer of cells and was associated with hyperkeratosis. Hyperplasia was found at multiple sites in the animals in addition to the skin, including the mouth palate, esophagus, forestomach, and exocervix. In multiple transgenic lineages, adult animals developed skin tumors late in life with low penetrance. These tumors arose from the squamous epithelia and from sebaceous glands and were characterized histologically to be highly differentiated, locally invasive, and aggressive in their growth properties. On the basis of these phenotypes, we conclude that HPV-16 E7 can alter epithelial cell growth parameters sufficiently to potentiate tumorigenesis in mice.

Reduction and glucuronidation of naftazone by human and rat liver microsomes

Reduction and glucuronidation of the vasoprotectant drug, naftazone, by human and rat liver microsomes and by recombinant UDP-glucuronosyltransferases (UGT) stably expressed in V79 cells were studied. The oxo group was first reduced in the presence of NADPH or NADH, and was subsequently readily glucuronidated on the phenolic moiety leading to a 1 beta-O-glucuronide, as revealed from MS and by proton and 13C-NMR. Glucuronide extracted from the urine of rats treated with the drug presented the same structure. In all enzyme systems tested, NADH was the most efficient electron donor, when compared with NADPH. The reaction was strongly inhibited by quercitrin, a specific inhibitor of carbonyl reductase. Attempts to isolate the reduced intermediate were unsuccessful because of its marked instability. In humans, a large interindividual variation for the formation of glucuronide was observed with microsomes of seven different liver samples (3.98 +/- 3.22 nmol/min.mg). In rat, glucuronidation of reduced naftazone was strongly induced (12-fold) by 3-methylcholanthrene and, to a lesser extent (2.6-fold) by phenobarbital, but was not affected by clofibrate. In addition, liver microsomes from Gunn rats, which present a genetic defect in bilirubin and phenol UGTs could not form glucuronide of reduced naftazone. The drug, after addition of NADH, was a substrate of the human liver recombinant UGT1*6 that presents a strict specificity toward planar phenolic substances, but not that of UGT2B4 and UGT2B1 expressed in V79 fibroblasts. The reducing step by the endogenous V79 cellular reductase was rate-limiting. In conclusion, the powerful inducing effect exerted by 3-methylcholanthrene, the lack of glucuronidation in the Gunn rat and the ability of UGT1*6 encoded by the UGT1 gene to glucuronidate reduced naftazone suggest that, in humans and in the rat, the compound is metabolized by a UGT isoform (UGT1*6 and the rat orthologous form) belonging to family 1, with a restricted specificity toward the drug.

The chemical modification of human liver UDP-glucuronosyltransferase UGT1*6 reveals the involvement of a carboxyl group in catalysis

The treatment of UDP-glucuronosyltransferase UGT1*6 stably expressed in V79 cells with three carboxyl-specific reagents, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-ethyl-5-phenylisoxazolium-3'-sulfonate (Woodward's reagent K), resulted in a fast, dose-dependent decrease of the 4-methylumbelliferone glucuronidation. The inactivation reactions followed pseudo-first order kinetics. The pKa of the modified residue was close to 5.0. A partial protection against inactivation by Woodward's reagent was observed at pH 7.4 in the presence of UDP-glucuronic acid, UDP, and, to a lesser extent, in the presence of 4-methylumbelliferone. Dicyclohexylcarbodiimide significantly decreased the Vmax, without affecting the apparent Km towards UDP-glucuronic acid and 4-methylumbelliferone. The results support the involvement of a carboxyl group in the catalytic process.

Differential effects of human recombinant interleukin-1 beta and dexamethasone on hepatic drug-metabolizing enzymes in male and female rats

Interleukin-1 beta (IL-1) is one of the major inflammation mediators, commonly reported to be an inhibitor of hepatic drug metabolism. We studied the effect of IL-1 treatment on various drug-metabolizing enzymes in male and female rats. IL-1 induced both cytochrome P450 (P450) 3A1 activity and protein in females, but in males, IL-1 repressed P450 3A2 activity, without decreasing the protein. P450 1A1 was impaired in males, but was retained after dexamethasone pretreatment. IL-1 did not change P450 2B1/2 activity and protein, but counteracted their induction by dexamethasone. Uridine diphospho-glucuronosyltransferase (UGT) 1A2 (bilirubin) activity and its induction by dexamethasone were not affected by IL-1 treatment. Both P450 2C11 and epoxide hydrolase activities were repressed by IL-1 treatment, and both activities were impaired after dexamethasone treatment. These results clearly demonstrate that IL-1 acts at different steps of protein synthesis and gene expression. The effect of IL-1 on P450 was isoform-dependent, indicating that IL-1 can act on pretranscriptional events. The discrepancy between the variations of the activities and the protein of P450 3A2 suggests a post-translational regulation. For P450 2C11, 3A1, and for microsomal epoxide hydrolase, but not for P450 1A1 and 2B1/2, IL-1 mimics the glucocorticoid effects. These differential effects can affect the kinetics and the bioavailability of drugs used in pathologies in which IL-1 is increased.