Corneal topography in Ehlers-Danlos syndrome

PURPOSE

To assess the use of corneal topography in conjunction with slitlamp biomicroscopy and retinoscopy to diagnose keratoconus in a large group of patients with Ehlers-Danlos syndrome (EDS).

SETTING

Kresge Eye Institute, Wayne State University, Detroit, Michigan, USA.

METHODS

Thirty-six patients (72 eyes) with genetically typed EDS had slitlamp biomicroscopy, retinoscopy, and videokeratography with the EyeSys instrument. The presence or absence of slitlamp keratoconus findings was correlated to a presumptive diagnosis based on corneal topography using derived topographic indexes associated with keratoconus. These topographic indexes included central corneal power, (CCP), difference in CCP, inferosuperior asymmetry (I-S) value, and asphericity (Q). Axial and profile difference maps were generated and analyzed for findings suggestive of keratoconus.

RESULTS

In 72 eyes, no keratoconus was found using slitlamp biomicroscopy. No eye had an I-S value greater than 1.60 diopters (D), 2 eyes had a CCP greater than 46.50 D, and 2 eyes had a Q value less than -1.00. Eight of 36 pairs of eyes had an intereye CCP greater than 0.92 D. In both eyes of the patient with Q values less than -1.00 the profile difference maps were mildly abnormal.

CONCLUSIONS

Slitlamp biomicroscopy of the cornea was unremarkable in all patients. Only 1 patient had Q values and profile difference maps that were mildly suggestive of keratoconus. Even after adding topography to the examination, it appears that keratoconus in a known population of patients with EDS remains rare.

Immunocytochemical study on the distribution of NOS-immunoreactive neurons in the cerebral cortex of aged rats

Nitric oxide (NO) involvement has been demonstrated in mechanisms of synaptic plasticity, particularly in hippocampal long-term potentiation, a mechanism that underlies certain forms of learning and memory. Several findings suggest that NO production may be decreased in the aged rats. Changes in the nNOS-containing neurons with ageing were demonstrated by immunocytochemistry. NOS-immunoreactive (IR) cells in aged rats were present in all cortical areas and the hippocampus, and the pattern of distribution was similar to that of the control group. The number of NOS-IR cells in the cerebral cortex was significantly decreased in the aged rats, but the extent of changes was variable in each area, and ranged from mild decrease (< 30%) to severe decrease (> 50%). Severely decreased areas were the cingulate cortex, parietal cortex area 1, temporal cortex area 1, 2, 3, medial part of occipital cortex area 2, monocular and binocular part of occipital cortex area 1, entorhinal cortex, hippocampus proper, dentate gyrus and subiculum. Morphologically, the number of dendritic branches seemed to be decreased in aged group and the length of dendrites of NOS-IR neurons showed a tendency to shorten. These results indicate the involvement of neuronal system containing NOS in the ageing brain, and provide the first morphological evidence for the loss of NOS neurons in the cerebral cortex of the aged rats by immunocytochemistry.

Decrease of capsular opacification with adjunctive mitomycin C in combined glaucoma and cataract surgery

OBJECTIVE

The authors investigated the incidence of capsular opacification requiring YAG capsulotomy after primary trabeculectomy combined with phacoemulsification and implantation of all polymethylmethacrylate intraocular lenses.

DESIGN

A prospective randomized study.

PARTICIPANTS

One hundred seventy-four eyes of 174 nonselected patients with primary open-angle glaucoma (POAG) were randomized to either no adjunctive mitomycin C (MMC) control group of 93 eyes of 93 patients) or adjunctive subconjunctival MMC (MMC group of 81 eyes of 81 patients) during the primary glaucoma triple procedure (PGTP).

INTERVENTION

Primary glaucoma triple procedure with and without MMC and YAG laser capsulotomy for posterior capsular opacification (PCO) was performed.

MAIN OUTCOME MEASURES

The incidences of YAG capsulotomy for PCO were compared between the control and MMC groups and also between the control group and the MMC subgroups (1 minute, 3 minutes, and 5 minutes of MMC application) using Kaplan-Meier analysis with Mantel-Cox log-rank test. Cox proportional hazard regression analysis also was performed to identify significant factors affecting capsular opacification.

RESULTS

The control and MMC groups were similar in preoperative characteristics. However, the probability of PCO requiring YAG capsulotomy was significantly lower in the MMC group than in the control group (P = 0.004). Among the MMC subgroups, MMC application for 3 minutes was most effective and significant when compared with that of the control group (P = 0.002). Although not as significant as the intraoperative use of MMC (P = 0.002), old age (P = 0.026) and presence of diabetes mellitus (P = 0.035) were also identified as significant beneficial factors for decreasing the incidence of YAG capsulotomy for PCO in Cox proportional hazard regression analysis.

CONCLUSION

Intraoperative subconjunctival MMC application during combined glaucoma and cataract surgery has a beneficial effect of inhibiting PCO after combined surgery in patients with POAG. Thus, after intraoperative subconjunctival application of MMC at the concentration of 0.5 mg/ml for 3 minutes, the aqueous MMC level must have been great enough to inhibit the lens epithelial cell proliferation to result in a long-term decrease in PCO.

Long-term outcome of primary glaucoma triple procedure with adjunctive 5-fluorouracil

PURPOSE

To evaluate the long-term effect of adjunctive subconjunctival 5-fluorouracil (5-FU) on the filtration outcome of primary glaucoma triple procedure (PGTP) in primary open-angle glaucoma (POAG) patients.

METHODS

Seventy-four POAG patients were randomly assigned to PGTP alone (36 patients) or PGTP with adjunctive subconjunctival 5-FU (5.0 +/- 1.3 injections of 5 mg each, total of 24.8 mg) (38 patients). After surgery, the patients were examined at regular intervals for intraocular pressure (IOP), visual acuity, medical therapy requirements, and complications. Surgical success was defined as IOP < or = 20 mmHg on postoperative medication < or = 1 without additional glaucoma surgery.

RESULTS

Over an average follow-up (+/- SD) of 45.3 +/- 25.0 months, both 5-FU and control groups maintained significant improvement of IOP control and visual acuity. However, there were no statistically significant differences between the 5-FU and control groups with respect to postoperative IOP, number of glaucoma medications, visual acuity outcome, and success rate overall or in selected patients with one or more of the risk factors for filtration failure.

CONCLUSIONS

The use of low-dose subconjunctival 5-FU (mean dosage of 24.8 mg in 5.0 +/- 1.3 injections) as an adjunct did not significantly improve the long-term filtration outcome of PGTP in POAG patients.

Magnone A and B, novel anti-PAF tetrahydrofuran lignans from the flower buds of Magnolia fargesii

In a search for platelet-activating-factor (PAF) antagonists, two new lignan compounds were isolated from the Chinese crude drug shin-i, the flower buds of Magnolia fargesii. Their structures were elucidated as (2S,3R,4R)-tetrahydro-2-(3,4-dimethoxyphenyl)-4-(3, 4-dimethoxybenzoyl)-3-(hydroxymethyl)furan (magnone A, 1) and (2S,3R, 4R)-tetrahydro-2-(3,4,5-trimethoxyphenyl)-4-(3, 4-dimethoxybenzoyl)-3-(hydroxymethyl)furan (magnone B, 2). Magnones A and B showed antagonistic activity against PAF in the [3H]PAF receptor binding assay with the IC50 values of 3.8 x 10(-5) M and 2.7 x 10(-5) M, respectively.

Localization of transferrin binding protein in relation to iron, ferritin, and transferrin receptors in the chicken cerebellum

We have demonstrated that transferrin binding protein (TfBP), ferritin, and iron, are specifically localized in Bergmann glia, while the transferrin receptor is confined to Purkinje cells in the chicken cerebellum. The results of this study suggest that Bergmann glia have previously undescribed functions related to iron regulation such as sequestration of iron and the maintenance of iron homeostasis in the cerebellum.

Reactive astrocytes express nitric oxide synthase in the spinal cord of transgenic mice expressing a human Cu/Zn SOD mutation

The distribution of the neuronal isoform of nitric oxide synthase (nNOS) in the spinal cord of transgenic mice expressing a mutated human copper/zinc superoxide dismutase gene was enhanced when investigated by immunocytochemistry. Immunocytochemistry showed intensely stained NOS-immunoreactive (IR) glial cells with the appearance of astrocytes in the spinal cord and brain stem of transgenic mice, but none were observed at these sites in control mice. Using antisera directed against GFAP, the specific marker for astrocyte, the glial cells were confirmed by immunocytochemistry to be astrocytes. This immunocytochemical evidence suggests that nitric oxide may mediate glutamate neurotoxicity, and this study provides the first in vivo evidence that nitric oxide may be implicated in the pathologic process of human familial amyotrophic lateral sclerosis.

Comparison of solution and crystal structures of maize nonspecific lipid transfer protein: a model for a potential in vivo lipid carrier protein

The three-dimensional solution structure of maize nonspecific lipid transfer protein (nsLTP) obtained by nuclear magnetic resonance (NMR) is compared to the X-ray structure. Although both structures are very similar, some local structural differences are observed in the first and the fourth helices and in several side-chain conformations. These discrepancies arise partly from intermolecular contacts in the crystal lattice. The main characteristic of nsLTP structures is the presence of an internal hydrophobic cavity whose volume was found to vary from 237 to 513 A3 without major variations in the 15 solution structures. Comparison of crystal and NMR structures shows the existence of another small hollow at the periphery of the protein containing a water molecule in the X-ray structure, which could play an important structural role. A model of the complexed form of maize nsLTP by alpha-lysopalmitoylphosphatidylcholine was built by docking the lipid inside the protein cavity of the NMR structure. The main structural feature is a hydrogen bond found also in the X-ray structure of the complex maize nsLTP/palmitate between the hydroxyl of Tyr81 and the carbonyl of the lipid. Comparison of 12 primary sequences of nsLTPs emphasizes that all residues delineating the cavities calculated on solution and X-ray structures are conserved, which suggests that this large cavity is a common feature of all compared plant nsLTPs. Furthermore several conserved basic residues seem to be involved in the stabilization of the protein architecture.

Comparison between high-pass resolution perimetry and differential light sensitivity perimetry in patients with glaucoma

PURPOSE

High-pass resolution perimeters such as the Ophthimus (High Tech Vision, Malmö, Sweden) may provide an easier, faster assessment of the visual field than conventional perimeters such as the Humphrey (Humphrey Instruments Inc., San Leandro, CA, U.S.A.), which is based on differential light sensitivity. The Ophthimus provides global indices and statistical analyses conceptually similar to those produced by the Humphrey. In addition, the Ophthimus provides, as a unique parameter, the estimated neural capacity.

PATIENTS AND METHODS

Twenty-one patients with chronic open-angle glaucoma and reliable fields on both Humphrey and Ophthimus testing were evaluated. The results from the two different techniques were compared.

RESULTS

The estimated neural capacity was correlated to global deviation and mean deviation at a statistically significant level. There were also correlations between mean deviation and global deviation and between pattern standard deviation and local deviation, but not between retest standard deviation and short-term fluctuation.

CONCLUSION

It is not clear at this point if the neural capacity of the Ophthimus provides any clinically useful information over and above global deviation. Mean test time was shorter with the Ophthimus system than the Humphrey. Performance on the reliability indices was better for the Ophthimus. The Ophthimus may prove useful in following patients with glaucoma.

Roles of the catalytic domain and two cellulose binding domains of Thermomonospora fusca E4 in cellulose hydrolysis

Thermomonospora fusca E4 is an unusual 90.4-kDa endocellulase comprised of a catalytic domain (CD), an internal family IIIc cellulose binding domain (CBD), a fibronectinlike domain, and a family II CBD. Constructs containing the CD alone (E4-51), the CD plus the family IIIc CBD (E4-68), and the CD plus the fibronectinlike domain plus the family II CBD (E4-74) were made by using recombinant DNA techniques. The activities of each purified protein on bacterial microcrystalline cellulose (BMCC), filter paper, swollen cellulose, and carboxymethyl cellulose were measured. Only the whole enzyme, E4-90, could reach the target digestion of 4.5% on filter paper. Removal of the internal family IIIc CBD (E4-51 and E4-74) decreased activity markedly on every substrate. E4-74 did bind to BMCC but had almost no hydrolytic activity, while E4-68 retained 32% of the activity on BMCC even though it did not bind. A low-activity mutant of one of the catalytic bases, E4-68 (Asp55Cys), did bind to BMCC, although E4-51 (Asp55Cys) did not. The ratios of soluble to insoluble reducing sugar produced after filter paper hydrolysis by E4-90, E4-68, E4-74, and E4-51 were 6.9, 3.5, 1.3, and 0.6, respectively, indicating that the family IIIc CBD is important for E4 processivity.

The role of adjunctive mitomycin C in secondary glaucoma triple procedure as compared to primary glaucoma triple procedure

OBJECTIVE

This study aimed to investigate whether previously failed glaucoma filtration surgery is a risk factor for filtration failure of subsequent trabeculectomy combined with cataract surgery and to determine the role of adjunctive mitomycin C (MMC) in the secondary glaucoma triple procedure (SGTP) as compared to primary glaucoma triple procedure (PGTP).

DESIGN

A prospective, controlled study that was randomized with respect to assignment to adjunctive MMC and a case-control design with respect to comparisons between SGTP and PGTP was studied.

PARTICIPANTS

The SGTP group consisted of 49 eyes of 49 consecutive patients with primary open-angle glaucoma with a history of glaucoma filtration surgery requiring glaucoma medical therapy and in need of cataract surgery, randomized to adjunctive MMC (SGTP MMC subgroup of 21 eyes) and no adjunctive MMC (SGTP control subgroup of 28 eyes). The PGTP group consisted of 49 PGTP cases closely matched to the SGTP cases with respect to age, race, gender, MMC use, C:D ratio, and systemic diseases.

INTERVENTION

Trabeculectomy combined with phacoemulsification and a small incision (5 x 6 mm), all polymethylmethacrylate posterior chamber intraocular lens implantation with or without adjunctive MMC (0.5 mg/ml for 1 minute), was performed.

MAIN OUTCOME MEASURES

Surgery failure was defined as the need of an additional intraocular procedure or the need of more than one medication to achieve intraocular pressure control to the target level. Intragroup and intergroup comparisons were made with respect to filtration outcome among the SGTP and PGTP patients.

RESULTS

Without adjunctive MMC, filtration success was significantly less in SGTP than in PGTP (P = 0.03). Adjunctive MMC significantly increased the success rate of SGTP (P = 0.02) but not that of PGTP (P = 0.89) over the average follow-up period of 2 years.

CONCLUSIONS

Previously failed glaucoma filtration surgery is a significant risk factor for the filtration failure of combined surgery. Intraoperative use of adjunctive MMC significantly improves the filtration success rate of SGTP.

Limbus-based vs fornix-based conjunctival flap in combined glaucoma and cataract surgery with adjunctive mitomycin C

PURPOSE

To determine the efficacy and safety of limbus-based vs fornix-based conjunctival flaps in patients with primary open-angle glaucoma undergoing trabeculectomy combined with phacoemulsification and intraocular lens implantation with adjunctive subconjunctival mitomycin C.

METHODS

In a prospective study, 69 eyes of 69 patients with primary open-angle glaucoma, visually symptomatic cataracts, and no previous incisional ocular surgery were randomly assigned to limbus-based and fornix-based conjunctival flap groups. All patients received trabeculectomy combined with phacoemulsification and posterior chamber lens implantation with 1-minute (0.5 mg/ ml) application of subconjunctival mitomycin C.

RESULTS

The mean intraocular pressures were significantly (P < .05) lower on significantly (P < .05) fewer medications postoperatively at 1 week, 1 month, 3, 6, 9, 12, and 15 to 18 months, and at last follow-up in both groups than they had been preoperatively. However, there were no significant (P > .05) differences in postoperative mean intraocular pressure, mean number of medications, and visual acuity between the two groups at any time interval. Hypotony with wound leak was significantly (P = .019) higher in the limbus-based group. Other postoperative complications were not significantly (P > .05) different between the two groups.

CONCLUSIONS

There was no notable difference in glaucoma control or visual outcome between limbus-based and fornix-based conjunctival flaps in primary trabeculectomy combined with phacoemulsification and lens implantation with adjunctive subconjunctival mitomycin C. The fornix-based flap was as safe as, if not safer than, the limbus-based flap in the glaucoma triple procedure with adjunctive subconjunctival mitomycin C.

Primary glaucoma triple procedure in patients with primary open-angle glaucoma: the effect of mitomycin C in patients with and without prognostic factors for filtration failure

PURPOSE

To investigate the effect of adjunctive mitomycin C on primary glaucoma triple procedure in patients with primary open-angle glaucoma with and without one or more of the prognostic factors for filtration failure of primary glaucoma triple procedure. Those factors include being of African-American race, having a preoperative intraocular pressure of 20 mm Hg or more on maximum tolerated medications, and being on two or more medications preoperatively.

METHODS

Study patients consisted of 197 consecutive patients with primary open-angle glaucoma who were randomly assigned to receive either no adjunctive mitomycin C (101 eyes of 101 patients) or to receive adjunctive subconjunctival mitomycin C (96 eyes of 96 patients) during the primary glaucoma triple procedure. Kaplan-Meier survival analysis comparisons were made between respective subgroups with and without prognostic indicators for filtration failures using a relatively stringent set of criteria for filtration success of primary glaucoma triple procedure.

RESULTS

There was no statistically significant (P = .117) difference in filtration success of primary glaucoma triple procedure between the control and mitomycin C groups. Adjunctive mitomycin C significantly (P < .05) improved the filtration outcome of the primary glaucoma triple procedure in the subgroups with each of the three prognostic factors for filtration failure of primary glaucoma triple procedure. On the other hand, in the subgroups without the prognostic factors, adjunctive mitomycin C did not significantly (P > .05) change the filtration outcome of the primary glaucoma triple procedure.

CONCLUSION

These findings establish the basis for selective use of mitomycin C in patients with primary open-angle glaucoma undergoing primary glaucoma triple procedure.

Rice non-specific lipid transfer protein: the 1.6 A crystal structure in the unliganded state reveals a small hydrophobic cavity

This study describes the high-resolution X-ray structure of the non-specific lipid transfer protein (ns-LTP) from rice seeds in the unliganded state. The model has been refined to a crystallographic R-factor of 0.186 for 8.0 to 1.6 A data (with Fo > 2 sigma F). It accounts for all 91 amino acid residues, 68 water molecules, one sulfate ion, and two molecules of 3-[cyclohexylamino]-1-propanesulfonic acid. The root-mean-square deviations from ideal bond lengths and angles are 0.017 A and 1.76 degrees, respectively. The overall fold of rice ns-LTP is very similar to that of maize ns-LTP. A superposition of 91 common C alpha atoms in rice and maize ns-LTPs, both in the unliganded state, gives a root-mean-square deviation of 1.2 A. Large structural differences from the crystal structure of maize ns-LTP are observed in two regions: the loop between two alpha-helices H1 and H2, where one residue deletion (Gln21 of maize sequence) occurs, and the C-terminal region around Tyr79. The C-terminal region of rice protein is somewhat collapsed into the hydrophobic cavity. As a consequence, its hydrophobic cavity is considerably smaller than that of maize protein (144 A3 versus 408 A3 for van der Waals cavity volumes), despite a high level of sequence identity (79%) between them. In the rice ns-LTP structure, the side-chain of Arg44 partially blocks the mouth of the cavity, while the side-chain of Ile81 effectively closes the other end by protruding into the cavity. And the side-chain of Tyr79 divides the cavity into two parts, with the larger part being shielded from the solvent. The present study illuminates the structure-function relationship of rice ns-LTP and allows a detailed structural comparison with other plant ns-LTPs.

Molecular characterization of tobacco squalene synthase and regulation in response to fungal elicitor

The enzyme squalene synthase (SS) represents the first commitment of carbon from the general isoprenoid pathway toward sterol biosynthesis and is a potential point for regulation of sterol biosynthesis. The isolation and characterization of tobacco (Nicotiana tabacum) squalene synthase (TSS) cDNA and genomic DNA clones, as well as determination of the steady state level of TSS mRNA in response to elicitor treatment, were investigated. cDNA clones for TSS were isolated from poly (A)+ RNA using a reverse transcription/polymerase chain reaction (RT/PCR) method. A 1233-bp cDNA clone was generated that contained an open reading frame of 411 amino acids giving a predicted molecular mass of 46.9 kDa. Comparison of the TSS deduced amino acid sequence with currently described SS from different species showed the highest identify with Nicotiana benthamiana (97%), followed by Glycyrrhiza glabra (81%), Arabidopsis thaliana (74%), rat (40%), and yeast (37%). Expression of a soluble form of the TSS enzyme with enzymatic activity in Escherichia coli was achieved by truncating 24 hydrophobic amino acids at the carboxy terminus. Characterization of genomic TSS (gTSS) revealed a gene of 7.086 kb with a complex organization of small exons and large introns not typical of plant genes. Southern blot hybridization indicated only two copies of the SS gene in the tobacco genome. Treatment of tobacco cell suspension cultures with a fungal elicitor dramatically reduced TSS enzymatic activity, lowering it to zero within 24 h. Analysis of TSS mRNA levels, by RNA blot hybridization and primer extension assays, in elicitor-treated cells indicated that the transcript level remained largely unchanged over this 24-h period. These results suggest that the suppression of TSS enzyme activity in elicitor-treated cells may result from a posttranscriptional modification of TSS.

Optical Implementation of the Hough Transform by use of rotationally multiplexed holograms

We show that the Hough transform filter can be obtained easily byuse of rotational multiplexing. To demonstrate our methodexperimentally, we recorded the Hough transform filter for 18 discreteprojection angles and compared experimental transform results with simulated ones for a few input patterns.

Momordins inhibit both AP-1 function and cell proliferation

The activation of Jun/Fos is a crucial factor in transmitting the tumor promoting signal from the extracellular environment to nuclear transcription machinery. One of the final steps in signal transduction is the binding of Jun/Fos to the AP-1 site in order to express gene transcription. Utilizing this concept, we screened about 100 extracts of natural plants to search for a Jun-Fos function inhibitor. The methanol extract of Ampelopsis radix reduced Jun/Foc retardation remarkably. The active principles of the extract were isolated and purified by repeated column chromatography and their structures were identified as oleanolic acid glycosides known as momordin I, Id, and Ie. These compounds reduced the Jun/Fos-DNA interaction and their activities were quantitated with liquid scintillation counting of corresponding bands. Among them, momordin I had the strongest inhibitory activity, with an IC50 value of 22.8 micrograms/ml. The methanol extract and momordin I, Id and Ie also showed cell cytotoxicity against human cancer cell lines. As expected from a gel shift assay, momordin I showed the strongest cytotoxicity and its IC50 value was from 7.280 micrograms/ml to 16.05 micrograms/ml depending on the cell line. With these data, it may be concluded that the mechanism of anticancer activity of momordin I comes from its inhibitory effect on the protein-DNA interaction. The in vivo test was done only with the methanol extract. The extract showed measurable anticancer activity against murine colon cancer. The wet tumor weight reduction rate was 17.73% at 90 mg/kg dose. We suggest that the Jun/Fos-DNA interaction results in cell cytotoxicity.

[A study on the movement for establishing a private isolation hospital under the rule of Japanese imperialism]

Koreans had an ill feeling against the only public isolation hospital, and their ill feeling was a cause the movement for establishing a private isolation hospital. The bad seating capacity and the nearness to downtown of public isolation hospital, and some violence caused in the course of taking a patient to the public isolation hospital were concrete causes of the movement for establishing a private isolation hospital. The three purposes of the movement for establishing a private isolation hospital are as follows. First, for the purpose of removing the national ill feeling, Koreans had to establish the isolation hospital by themselves. Second, for the purpose of curing the patients, doctors needed to use Oriental medicine together. Third, for the purpose of doing away with the anxiety of infection, the isolation hospital had to be located in a distant place from downtown. The movement for establishing a private isolation hospital didn't succeed. It only ended up establishing a contagious ward in Severance hospital. Because whenever an isolation hospital was planned to be constructed somehere, the residents worrying about the infection opposed to the construction, and enough money didn't be gathered. Abve all, rich pro-Japanese men didn't contribute enough money. The middle and lower classes contributed almost all of the money. The movement for estabishing a private isolation hospital was the extension of anti-Japanese national feeling that sprung from the March 1st movement. In view of strenghtening Korean ability, the movement for establishing a private isolation hospital had a common cause with the Shilryokyangsong movement in the early 1920s.

Crystal structure of carboxylesterase from Pseudomonas fluorescens, an alpha/beta hydrolase with broad substrate specificity

BACKGROUND

A group of esterases, classified as carboxylesterases, hydrolyze carboxylic ester bonds with relatively broad substrate specificity and are useful for stereospecific synthesis and hydrolysis of esters. One such carboxylesterase from Pseudomonas fluorescens is a homodimeric enzyme, consisting of 218-residue subunits. It shows a limited sequence similarity to some members of the alpha/beta hydrolase superfamily. Although crystal structures of a number of serine esterases and lipases have been reported, structural information on carboxylesterases is very limited. This study was undertaken in order to provide such information and to understand a structural basis for the substrate specificity of this carboxylesterase.

RESULTS

In this study, the crystal structure of carboxylesterase from P. fluorescens has been determined by the isomorphous replacement method and refined to 1.8 A resolution. Each subunit consists of a central seven-stranded beta sheet flanked by six alpha helices. The structure reveals the catalytic triad as Ser 114-His 199-Asp 168. The structure of the enzyme in complex with the inhibitor phenylmethylsulfonyl fluoride has also been determined and refined to 2.5 . The inhibitor is covalently attached to Ser 114 of both subunits, with the aromatic ring occupying a hydrophobic site defined by the aliphatic sidechains of Leu23, Ile58, Ile70, Met73 and Val170. No large structural changes are observed between the free and inhibitor-bound structures.

CONCLUSIONS

Carboxylesterase from P. fluorescens has the alpha/beta hydrolase fold and the Ser-His-Asp catalytic triad. The active-site cleft in each subunit is formed by the six loops covering the catalytic serine residue. Three of the active-site loops in each subunit are involved in a head-to-head subunit interaction to form a dimer; it may be these extra structural elements, not seen in other esterases, that account for the inability of carboxylesterase to hydrolyze long chain fatty acids. As a result of dimerization, the active-site clefts from the two subunits merge to form holes in the dimer. The active-site clefts are relatively open and thus the catalytic residues are exposed to the solvent. An oxyanion hole, formed by nitrogen atoms of Leu23 and Gln115, is present in both the free and inhibitor-bound structures. An open active site, as well as a large binding pocket for the acid part of substrates, in P. fluorescens carboxylesterase may contribute to its relatively broad substrate specificity.

Investigation of certain diffraction effects in an optical disk

We report certain diffraction effects that are pertinent to the operation of double-layer optical recording media. For simulating cross-talk effects for double layers, the diffraction of light from the out-of-focus layer and the resulting distribution on the in-focus layer are studied by use of computer simulations. The findings are then verified qualitatively by direct measurements. We also describe a technique for analyzing (by computer simulation) the focus-error signal (FES), taking into account the cross talk between two layers, in systems that use the astigmatic method in conjunction with the double-layer disk. The results of our computer simulations of the FES give us a 10% cross-talk contribution to the original signal. The results of the FES evaluation are compared with those measured in an actual disk drive; good agreement between computation and measurement is obtained.

The effect of adjunctive mitomycin C in Molteno implant surgery

PURPOSE

The purpose of the study is to assess the effect of adjunctive intraoperative mitomycin C (MMC) in Molteno drainage device implantation for patients with recalcitrant glaucomas.

METHOD

Forty-nine eyes of 49 patients who underwent one-stage, single-plate Molteno device implantation with adjunctive intraoperative MMC (0.5 mg/ml) for 3 to 5 minutes (MMC group) were compared to a historic control group of 51 eyes of 51 patients (control group) who received one-stage, single-plate Molteno device implantation without MMC. Success (survival) was defined as an intraocular pressure (IOP) between 6 and 21 mmHg, inclusive, with (qualified success) or without (complete success) glaucoma medications and with no additional glaucoma surgery, phthisis, implant removal, or loss of light perception.

RESULTS

Preoperative conditions were similar between the two groups. There was no significant difference in surgical survival rate between the two groups (P = 0.13, log-rank test). There also were no significant differences in the postoperative IOP levels and numbers of antiglaucoma medications between the two groups at all times (P > 0.05). Visual acuity was improved or remained within one line of preoperative visual acuity in 76.1% of the MMC group and 78.7% of the control group at 1 year after surgery (P = 0.76, chi-square test). Complications and reoperation for complications were similar in both groups (P > 0.05, chi-square test) except for the incidence of early postoperative hypotony and the total number of eyes with complications not requiring reoperation, which were more common in the MMC group (P = 0.027, 0.005, respectively, chi-square test). The most common complications included hypotony with or without a flat anterior chamber or choroidal detachment, followed by hyphema and tube plugging.

CONCLUSION

Molteno device implantation with adjunctive intraoperative MMC in patients with complicated glaucoma may not offer a better chance of surgical success compared with Molteno implantation without MMC.

Pleomorphic adenoma of the trachea

A case of salivary gland type pleomorphic adenoma of the trachea in a 48-year-old woman is presented. Pleomorphic adenoma is extremely rare in the trachea. The behavior of this tumor in the trachea appears to be similar to its counterpart in other sites and distinctly different from the more frequently encountered epithelial tumors.

Intravascular lymphomatosis: a clinicopathological study of two cases presenting as an interstitial lung disease

AIMS

Intravascular lymphomatosis is an uncommon type of non-Hodgkin's lymphoma characterized by intravascular proliferation of neoplastic lymphoid cells. Although the tumour is basically a systemic disease, eventually involving multiple organs, primary presentation in the lung is rare.

METHODS AND RESULTS

We describe the clinicopathological features of two patients with intravascular lymphomatosis presenting in the lung. One patient complained of fever, headache and chest pain; the other, of dyspnoea on exertion and headache. Both patients showed reticulonodular density on chest radiography and decreased diffusion capacity. Lung biopsy showed features characteristic of intravascular lymphomatosis. Malignant lymphoid cells were CD30 positive T-cells of anaplastic large cell type in one patient and B-cells of large cell type in the other. There was a poor response to chemotherapy and both patients died of the disease within 3 months of diagnosis.

CONCLUSIONS

These cases and 10 previous reports illustrate the need to include intravascular lymphomatosis in the differential diagnosis of interstitial lung disease.

Laser trabeculoplasty: how little is enough?

BACKGROUND AND OBJECTIVE

The optimal number of laser applications for argon laser trabeculoplasty in patients with primary open-angle glaucoma has not been established. The purpose of this study was to determine the fewest number of burns necessary for clinically effective intraocular pressure reduction for these patients.

PATIENTS AND METHODS

Using a prospective, randomized, collaborative study, the authors examined the relationship between the number of laser trabeculoplasty burns and intraocular pressure for patients with primary open-angle glaucoma. A total of 122 patients received either 50 burns to half of the trabecular meshwork (group 1) or 35 burns to one third of the trabecular meshwork (group 2).

RESULTS

The mean baseline intraocular pressures were similar between group 1 (22.3 +/- 4.1 mm Hg [mean +/- SD]) and group 2 (22.8 +/- 5.0 mm Hg) (P = .58). Intraocular pressure reduction at 9 to 12 months, although significant in both groups (group 1: 4.4 +/- 3.0 mm Hg, P < .0001; group 2: 3.9 +/- 5.1 mm Hg, P < .0001), did not differ significantly between the two groups (P = .63).

CONCLUSION

This study demonstrated that 35 burns may be as clinically effective as 50 burns in reducing the intraocular pressure in primary open-angle glaucoma patients.

Chronic use of apraclonidine decreases its moderation of post-laser intraocular pressure spikes

OBJECTIVE

The purpose of the study is to investigate the efficacy of 1.0% apraclonidine in preventing intraocular pressure (IOP) spike after argon laser trabeculoplasty (ALT) in patients on chronic apraclonidine therapy compared with patients not on chronic apraclonidine use.

DESIGN

The study design was a prospective study.

PARTICIPANTS

This study consisted of 231 consecutive eyes of patients with primary open-angle glaucoma undergoing ALT: 70 eyes (30%) were started on a regimen including chronic apraclonidine 0.5% use (group A) and 161 eyes (70%) were started on a regimen without chronic apraclonidine 0.5% use (group B).

INTERVENTION

Both groups received one drop of apraclonidine 1.0% 15 minutes before ALT to 180 degrees of previously untreated trabecular meshwork. Intraocular pressure was measured before the procedure and at 5 minutes, 1 hour, and 24 hours after the laser treatment.

MAIN OUTCOME MEASURES

Incidences of an IOP spike and mean IOPs at 5 minutes, 1 hour, and 24 hours after the laser treatment were compared between the two groups. Multivariate logistic regression analysis also was carried out to identify the significant risk factors for post-ALT IOP spikes despite prophylactic apraclonidine 1.0% treatment.

RESULTS

The incidences of IOP spikes greater than 0 mmHg, greater than 2 mmHg, and greater than 5 mmHg at 1 hour after ALT were 32.9%, 22.9%, and 12.9%, respectively, in group A versus 13.7%, 11%, and 3.1%, respectively, in group B (P = 0.0007, P = 0.009, and P = 0.004). Chronic apraclonidine 0.5% use was found to be the only significant risk factor for IOP spikes at 1 hour after ALT by multivariate logistic regression analysis.

CONCLUSIONS

The incidences of IOP spikes in group A were significantly greater than in group B and approached the reported incidences of IOP spikes without perilaser apraclonidine prophylaxis. This indicates that peri-ALT apraclonidine is relatively ineffective in patients with chronic apraclonidine 0.5% use (group A) compared with patients without chronic apraclonidine use (group B), presumably because of saturation of the ocular alpha-2 receptors with apraclonidine in patients with chronic apraclonidine use. Therefore, in patients receiving chronic apraclonidine therapy, it is especially important to monitor their post-ALT IOPs and to be prepared to treat postlaser IOP spikes using agents other than apraclonidine.