Inactivation of peroxiredoxin I by phosphorylation allows localized H(2)O(2) accumulation for cell signaling

Despite its toxicity, H(2)O(2) is produced as a signaling molecule that oxidizes critical cysteine residues of effectors such as protein tyrosine phosphatases in response to activation of cell surface receptors. It has remained unclear, however, how H(2)O(2) concentrations above the threshold required to modify effectors are achieved in the presence of the abundant detoxification enzymes peroxiredoxin (Prx) I and II. We now show that PrxI associated with membranes is transiently phosphorylated on tyrosine-194 and thereby inactivated both in cells stimulated via growth factor or immune receptors in vitro and in those at the margin of healing cutaneous wounds in mice. The localized inactivation of PrxI allows for the transient accumulation of H(2)O(2) around membranes, where signaling components are concentrated, while preventing the toxic accumulation of H(2)O(2) elsewhere. In contrast, PrxII was inactivated not by phosphorylation but rather by hyperoxidation of its catalytic cysteine during sustained oxidative stress.

Inhibition of SARS-CoV 3CL protease by flavonoids

There were severe panics caused by Severe Acute Respiratory Syndrome (SARS) and Middle-East Respiratory Syndrome-Coronavirus. Therefore, researches targeting these viruses have been required. Coronaviruses (CoVs) have been rising targets of some flavonoids. The antiviral activity of some flavonoids against CoVs is presumed directly caused by inhibiting 3C-like protease (3CLpro). Here, we applied a flavonoid library to systematically probe inhibitory compounds against SARS-CoV 3CLpro. Herbacetin, rhoifolin and pectolinarin were found to efficiently block the enzymatic activity of SARS-CoV 3CLpro. The interaction of the three flavonoids was confirmed using a tryptophan-based fluorescence method, too. An induced-fit docking analysis indicated that S1, S2 and S3' sites are involved in binding with flavonoids. The comparison with previous studies showed that Triton X-100 played a critical role in objecting false positive or overestimated inhibitory activity of flavonoids. With the systematic analysis, the three flavonoids are suggested to be templates to design functionally improved inhibitors.

Q-switched 532-nm Nd:YAG laser trabeculoplasty (selective laser trabeculoplasty): a multicenter, pilot, clinical study

OBJECTIVE

To investigate the safety and efficacy of a new laser procedure using a q-switched 532-nm neodymium (Nd):YAG laser, also called "selective laser trabeculoplasty," to lower intraocular pressure (IOP) in patients with open-angle glaucoma (OAG). The laser parameters were set to selectively target pigmented trabecular meshwork (TM) cells without coagulative damage to the TM structure or nonpigmented cells.

DESIGN

Nonrandomized, prospective, clinical trial.

PARTICIPANTS

Thirty eyes of 30 patients with uncontrolled OAG (OAG group) and 23 eyes of 23 patients with uncontrolled OAG treated previously with argon laser trabeculoplasty (ALT group) were observed for 4 to 26 weeks. Forty-four of the 53 eyes were observed for 26 weeks.

INTERVENTION

Patients were treated with the Coherent Selecta 7000 (Coherent, Inc, Palo Alto, CA) frequency-doubled q-switched Nd:YAG laser (532 nm). A total of approximately 50 nonoverlapping spots were placed over 180 degrees of the TM at energy levels ranging from 0.6 to 1.2 mJ per pulse. After surgery, patients were maintained with the identical drug regimen as that before treatment.

RESULTS

Both the OAG and ALT groups showed similar IOP reductions over time. Seventy percent of patients in each group responded to treatment with an IOP reduction of least 3 mmHg. At 26 weeks of follow-up, mean IOP reduction was 5.8 mmHg (23.5%, P < 0.001) for the OAG group and 6.0 mmHg (24.2%, P < 0.001) for the ALT group. The untreated eye showed a 9.7% (P < 0.001) reduction of IOP at 26 weeks. However, the IOP difference between the treated and untreated eyes was statistically significant at P < 0.003. Transient IOP elevation of 5 mmHg or greater was seen in 24% of patients.

CONCLUSION

The selective laser trabeculoplasty appears to be a safe and effective method to lower IOP in patients with OAG and patients treated previously with ALT. A reduction of IOP can be achieved without coagulation of the TM.

The crystal structure of a triacylglycerol lipase from Pseudomonas cepacia reveals a highly open conformation in the absence of a bound inhibitor

BACKGROUND

. Lipases, a family of enzymes which catalyze the hydrolysis of triglycerides, are widely distributed in many organisms. True lipases are distinguished from esterases by the characteristic interfacial activation they exhibit at an oil-water interface. Lipases are one of the most frequently used biocatalysts for organic reactions performed under mild conditions. Their biotechnological applications include food and oil processing and the preparation of chiral intermediates for the synthesis of enantiomerically pure pharmaceuticals. Recent structural studies on several lipases have provided some clues towards understanding the mechanisms of hydrolytic activity, interfacial activation, and stereoselectivity. This study was undertaken in order to provide structural information on bacterial lipases, which is relatively limited in comparison to that on the enzymes from other sources.

RESULTS

. We have determined the crystal structure of a triacylglycerol lipase from Pseudomonas cepacia (PcL) in the absence of a bound inhibitor using X-ray crystallography. The structure shows the lipase to contain an alpha/beta-hydrolase fold and a catalytic triad comprising of residues Ser87, His286 and Asp264. The enzyme shares several structural features with homologous lipases from Pseudomonas glumae (PgL) and Chromobacterium viscosum (CvL), including a calcium-binding site. The present structure of PcL reveals a highly open conformation with a solvent-accessible active site. This is in contrast to the structures of PgL and PcL in which the active site is buried under a closed or partially opened 'lid', respectively.

CONCLUSIONS

. PcL exhibits some structural features found in other lipases. The presence of the Ser-His-Asp catalytic triad, an oxyanion hole, and the opening of a helical lid suggest that this enzyme shares the same mechanisms of catalysis and interfacial activation as other lipases. The highly open conformation observed in this study is likely to reflect the activated form of the lipase at an oil-water interface. The structure suggests that the interfacial activation of bacterial lipases involves the reorganization of secondary structures and a large movement of the lid to expose the active site. This is similar to the mechanism described for other well characterized fungal and mammalian lipases.

High-resolution crystal structure of the non-specific lipid-transfer protein from maize seedlings

BACKGROUND

The movement of lipids between membranes is aided by lipid-transfer proteins (LTPs). Some LTPs exhibit broad specificity, transferring many classes of lipids, and are termed non-specific LTPs (ns-LTPs). Despite their apparently similar mode of action, no sequence homology exists between mammalian and plant ns-LTPs and no three-dimensional structure has been reported for any plant ns-LTP.

RESULTS

We have determined the crystal structure of ns-LTP from maize seedlings by multiple isomorphous replacement and refined the structure to 1.9 A resolution. The protein comprises a single compact domain with four alpha-helices and a long C-terminal region. The eight conserved cysteines form four disulfide bridges (assigned as Cys4-Cys52, Cys14-Cys29, Cys30-Cys75, and Cys50-Cys89) resolving the ambiguity that remained from the chemical determination of pairings in the homologous protein from castor bean. Two of the bonds, Cys4-Cys52 and Cys50-Cys89, differ from what would have been predicted from sequence alignment with soybean hydrophobic protein. The complex between maize ns-LTP and hexadecanoate (palmitate) has also been crystallized and its structure refined to 1.8 A resolution.

CONCLUSIONS

The fold of maize ns-LTP places it in a new category of all-alpha-type structure, first described for soybean hydrophobic protein. In the absence of a bound ligand, the protein has a tunnel-like hydrophobic cavity, which is large enough to accommodate a long fatty acyl chain. In the structure of the complex with palmitate, most of the acyl chain is buried inside this hydrophobic cavity.

Characteristics of flavonoids as potent MERS-CoV 3C-like protease inhibitors

Middle East respiratory syndrome-coronavirus (MERS-CoV) is a zoonotic virus transmitted between animals and human beings. It causes MERS with high mortality rate. However, no vaccine or specific treatment is currently available. Since antiviral activity of some flavonoids is known, we applied a flavonoid library to probe inhibitory compounds against MERS-CoV 3C-like protease (3CLpro). Herbacetin, isobavachalcone, quercetin 3-β-d-glucoside and helichrysetin were found to block the enzymatic activity of MERS-CoV 3CLpro. The binding of the four flavonoids was also confirmed independently using a tryptophan-based fluorescence method. The systematic comparison of the binding affinity of flavonoids made it possible to infer their scaffolds and functional groups required to bind with MERS-CoV 3CLpro. An induced-fit docking analysis revealed that S1 and S2 sites play a role in interaction with flavonoids. The experimental and computational study showed that flavonol and chalcone are favourite scaffolds to bind with the catalytic site of MERS-CoV 3CLpro. It was also deduced that some flavonoid derivatives with hydrophobic or carbohydrate attached to their core structures have a good inhibitory effect. Therefore, we suggest that flavonoids with these characteristics can be used as templates to develop potent MERS-CoV 3CLpro inhibitors.

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.

Implantation of posterior chamber lens in the absence of capsular and zonular support

We have developed surgical techniques for implanting a posterior chamber lens in the absence of capsular and zonular support by securing both haptics of the posterior chamber lens to the sclera at the ciliary sulcus with 10-0 prolene suture. These techniques have been successfully performed and have produced good visual results in six monocularly aphakic patients who had contact lens intolerance and/or contraindications to anterior chamber lens implantations. In consideration of the high incidence and the great variety of complications associated with anterior chamber lenses, these newly developed surgical techniques will be a useful alternative to anterior chamber lenses, even in patients who do not have definite contraindications to anterior chamber lens implantations.

Use of a real time continuous glucose monitoring system as a motivational device for poorly controlled type 2 diabetes

OBJECTIVE

The use of a real time continuous glucose monitoring system (RT-CGM) was studied as a behavior modification tool and the effectiveness of a RT-CGM in glucose control for patients with type 2 diabetes was determined.

METHODS

We conducted a prospective, open-label, randomized, controlled clinical trial in 65 patients with poorly controlled type 2 diabetes (8.0</=HbA1c</=10%) over a 3-month period. The intervention group was monitored monthly with a RT-CGM (three days at a time for 3 months) and the control group continued self-monitoring blood glucose (SMBG) at least four times a week for 3 months.

RESULTS

The HbA1c of the RT-CGM group was significantly reduced after 12 weeks compared with the SMBG group (9.1+/-1.0% to 8.0+/-1.2% vs. 8.7+/-0.7% to 8.3+/-1.1%, respectively; P=0.004). In the RT-CGM group, there was a significant reduction in total daily calorie intake, weight, body mass index (BMI), and postprandial glucose level, and a significant increase in total exercise time per week after 3 months.

CONCLUSIONS

We demonstrated that the RT-CGM was useful in modifying a patient's diet and exercise habits and could induce better glycemic control than SMBG for patients with type 2 diabetes.

Risk factors for retinal vein occlusions. A case-control study

The authors conducted a case-control study of risk factors for retinal vein occlusions using 87 patients with vein occlusions, chosen randomly from photographic files from their institution between 1985 and 1990, and a control group of 85 subjects 38 years of age (the youngest individual in the vein occlusion group) or older, who were randomly selected from the records of two general ophthalmologists in the authors' department. Certain risk factors for retinal vein occlusion were highly significant when subjects with retinal vein occlusion were compared with the control group. These risk factors included systemic hypertension (odds ratio [OR], 3.86; 95% confidence interval [Cl], 2.08 to 7.16), open-angle glaucoma (OR, 2.89; 95% Cl, 1.38 to 6.05), and male sex (OR, 2.61; 95% Cl, 1.43 to 4.79). Race, presence of diabetes mellitus, history of coronary artery disease or stroke, and family history of diabetes, glaucoma, coronary artery disease, or stroke were not significant risk factors in the population studied. Logistic analysis of the risk factors showed no interactions. Risk factors for branch retinal vein occlusion and central retinal vein occlusion were identical.

Structural basis of non-specific lipid binding in maize lipid-transfer protein complexes revealed by high-resolution X-ray crystallography

Non-specific lipid-transfer proteins (nsLTPs) are involved in the movement of phospholipids, glycolipids, fatty acids, and steroids between membranes. Several structures of plant nsLTPs have been determined both by X-ray crystallography and nuclear magnetic resonance. However, the detailed structural basis of the non-specific binding of hydrophobic ligands by nsLTPs is still poorly understood. In order to gain a better understanding of the structural basis of the non-specific binding of hydrophobic ligands by nsLTPs and to investigate the plasticity of the fatty acid binding cavity in nsLTPs, seven high-resolution (between 1.3 A and 1.9 A) crystal structures have been determined. These depict the nsLTP from maize seedlings in complex with an array of fatty acids.A detailed comparison of the structures of maize nsLTP in complex with various ligands reveals a new binding mode in an nsLTP-oleate complex which has not been seen before. Furthermore, in the caprate complex, the ligand binds to the protein cavity in two orientations with equal occupancy. The volume of the hydrophobic cavity in the nsLTP from maize shows some variation depending on the size of the bound ligands. The structural plasticity of the ligand binding cavity and the predominant involvement of non-specific van der Waals interactions with the hydrophobic tail of the ligands provide a structural explanation for the non-specificity of maize nsLTP. The hydrophobic cavity accommodates various ligands from C10 to C18. The C18:1 ricinoleate with its hydroxyl group hydrogen bonding to Ala68 possibly mimics cutin monomer binding which is of biological importance. Some of the myristate binding sites in human serum albumin resemble the maize nsLTP, implying the importance of a helical bundle in accommodating the non-specific binding of fatty acids.

Molecular cloning and expression analysis of carp (Cyprinus carpio) interleukin-1 beta, high affinity immunoglobulin E Fc receptor gamma subunit and serum amyloid A

Suppression subtractive hybridisation (SSH) is a powerful means to identify genes of cytokines and other genes that express small amount of mRNA. In this study, cDNA of normal fish (carp) head kidney cells (HKC) was subtracted from pooled cDNA of HKC and peritoneal cell (PC) obtained from fish which had been injected with sodium alginate (SA) and scleroglucan (SG) 3-48 h earlier. This subtraction produced 248 clones of cDNA fragments. After sequencing some of the fragments of interest were used as probes, and yielded full-length cDNAs homologous to mammalian interleukin-1 beta (IL-1 beta), the gamma subunit of high affinity Fc receptor for IgE (Fc epsilon RI gamma) and serum amyloid A (SAA); these were cloned and sequenced. Carp IL-1 beta shows 21.8-24.7% amino acid identities to mammalian mature IL-1 beta, and lacks a signal sequence, which is consistent with mammalian IL-1 beta. Carp Fc epsilon RI gamma, which was the first cloned non-mammalian Fc receptor subunit, shows 39.3-40.4% amino acid identities to mammalian Fc epsilon RI gamma, and contains the immunoreceptor tyrosin-based activation motif characteristic of the signal transduction subunit of antigen- and Fc-receptors. Carp SAA is most similar to mammalian acute phase responsive type SAA with 53.0-55.3% amino acid identities. Both SA-elicited and SG-elicited PC expressed higher amounts of IL-1 beta and SAA mRNA compared to saline-injected fish HKC and PC, indicating that these proteins are associated with inflammatory responses, similar to mammalian homologues. Fc epsilon RI gamma was constitutively expressed in leucocytes and not immunopotentiator-responsive, but this indicates that Fc receptor including Fc epsilon RI gamma subunit is likely functional in the carp immune system.

Comparison of the Tono-Pen to the Goldmann applanation tonometer

Oculab Tono-Pen tonometry was compared with Goldmann applanation tonometry in 142 eyes of 71 patients without corneal problems. Overall we found 63% of the Tono-Pen readings to be within +/- 2 mm Hg of the Goldmann applanation tonometry readings and 77% to be within +/- 3 mm Hg, while 4% were within at least +/- 7 mm Hg difference. The correlation coefficient between the readings of the two instruments was .84. The mean value of the paired differences was 0.81 +/- 3.09 mm Hg overall, -1.78 +/- 1.86 mm Hg in the 4 to 10 mm Hg interval, 0.07 +/- 2.97 mm Hg in the 11 to 20 mm Hg interval, 1.27 +/- 2.62 mm Hg in the 21 to 30 mm Hg interval, and 4.15 +/- 2.28 mm Hg in the 31 to 45 mm Hg interval. We conclude that the Tono-Pen measures intraocular pressure in a manner that corresponds well to the Goldmann tonometer in the 11 to 20 mm Hg interval, and fairly well in the 4 to 10 mm Hg and 21 to 30 mm Hg intervals. It lacks good correspondence in the 31 to 45 mm Hg interval.

Adjunctive mitomycin C in primary trabeculectomy in phakic eyes

PURPOSE

The addition of antiproliferative agents, most recently mitomycin C, has improved the outcome of glaucoma filtering surgery in eyes with a high risk of surgical failure. We conducted the present study to determine whether adjunctive mitomycin C would increase the success rate of primary trabeculectomies in phakic eyes.

METHODS

Thirty-three eyes of 33 consecutive patients with phakic primary open-angle glaucoma, who were predominantly black (24 black and nine white), who underwent primary trabeculectomy with adjunctive subconjunctival mitomycin C (0.5 mg/ml for three minutes) were compared with a demographically similar historical control group of 30 eyes of 30 consecutive patients (20 black and ten white) with phakic primary open-angle glaucoma, who had undergone primary trabeculectomy without an adjunctive antifibrotic agent.

RESULTS

Although the mean preoperative intraocular pressures were similar in both groups (29.0 +/- 6.4 mm Hg in the mitomycin C group and 29.5 +/- 10.0 mm Hg in the control group, P = .61), the mean postoperative intraocular pressure at each follow-up period was significantly lower in the mitomycin C group than in the control group (10.3 +/- 7.1 vs 14.5 +/- 5.1 mm Hg at six months, P = .02; 10.5 +/- 4.9 vs 14.5 +/- 4.4 mm Hg at 12 months, P = .01; and 10.0 +/- 3.1 vs 17.2 +/- 3.0 mm Hg at 18 months, P = .004, respectively). The mean number of postoperative medications was also significantly lower in the mitomycin C group (0.2 +/- 0.4 vs 1.1 +/- 1.4 medications at six months, P = .007; 0.3 +/- 0.4 vs 0.9 +/- 1.1 medications at 12 months, P = .04; and 0.3 +/- 0.5 vs 1.7 +/- 1.2 medications at 18 months, P = .01, respectively). However, the mitomycin C group had a significantly higher incidence of prolonged hypotony (intraocular pressure less than 6 mm Hg) compared with the control group (15% vs 0% at nine months, P = .05). Younger age was associated with a higher incidence of persistent hypotony.

CONCLUSIONS

Adjunctive subconjunctival mitomycin C (0.5 mg/ml for a three-minute exposure) in primary trabeculectomies of phakic eyes, while increasing the success rate by decreasing intraocular pressure and postoperative medications, is associated with a higher incidence of prolonged hypotony.

Isolation, characterization, and functional analysis of a novel cDNA clone encoding a small rubber particle protein from Hevea brasiliensis

Biochemical evidence reported so far suggests that rubber synthesis takes place on the surface of rubber particles suspended in the latex of Hevea brasiliensis. We have isolated and characterized a cDNA clone that encodes a protein tightly bound on a small rubber particle. We named this protein small rubber particle protein (SRPP). Prior to this study, this protein was known as a latex allergen, and only its partial amino acid sequence was reported. Sequence analysis revealed that this protein is highly homologous to the rubber elongation factor and the Phaseolus vulgaris stress-related protein. Southern and Northern analyses indicate that the protein is encoded by a single gene and highly expressed in latex. An allergenicity test using the recombinant protein confirmed that the cloned cDNA encodes the known 24-kDa latex allergen. Neither ethylene stimulation nor wounding changed the transcript level of the SRPP gene in H. brasiliensis. An in vitro rubber assay showed that the protein plays a positive role in rubber biosynthesis. Therefore, it is likely that SRPP is a part of the rubber biosynthesis machinery, if not the rubber polymerase, along with the rubber elongation factor.

Flavonoids with inhibitory activity against SARS-CoV-2 3CLpro

Coronavirus disease 2019 (COVID-19) has been a pandemic disease of which the termination is not yet predictable. Currently, researches to develop vaccines and treatments is going on globally to cope with this disastrous disease. Main protease (3CLpro) from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the good targets to find antiviral agents before vaccines are available. Some flavonoids are known to inhibit 3CLpro from SARS-CoV which causes SARS. Since their sequence identity is 96%, a similar approach was performed with a flavonoid library. Baicalin, herbacetin, and pectolinarin have been discovered to block the proteolytic activity of SARS-CoV-2 3CLpro. An in silico docking study showed that the binding modes of herbacetin and pectolinarin are similar to those obtained from the catalytic domain of SARS-CoV 3CLpro. However, their binding affinities are different due to the usage of whole SARS-CoV-2 3CLpro in this study. Baicalin showed an effective inhibitory activity against SARS-CoV-2 3CLpro and its docking mode is different from those of herbacetin and pectolinarin. This study suggests important scaffolds to design 3CLpro inhibitors to develop antiviral agents or health-foods and dietary supplements to cope with SARS-CoV-2.

Endobronchial tuberculosis. Clinical and bronchoscopic features in 121 cases

The clinical and bronchoscopic features of endobronchial tuberculosis in 121 patients were retrospectively investigated. The peak incidence occurred in the second decades, with 3.8 times higher incidence noted in female than in male subjects. A barking cough with sputum was the most common chief complaint in 61.1 percent. Parenchymal infiltration and/or consolidation was the most common roentgenographic finding of the chest in 58.6 percent. Hypertrophy with luminal narrowing was the most common bronchoscopic finding in 43 percent. Bronchoscopically, right upper and right main bronchus were the most frequently involved in 30.5 percent. It was concluded from these data that using fiberoptic bronchoscopy allows not only substantial meaningful assessment of endobronchial tuberculosis but also relieves atelectasis eventually resulting in successful treatment with antituberculosis drugs.

Diffusion tensor imaging in patients with essential tremor

BACKGROUND AND PURPOSE

The traditional paradigm has regarded essential tremor (ET) as a benign disorder. However, recent clinical, neuroimaging, and neuropathologic studies suggest that ET may be a progressive neurologic disorder. Based on clinicopathologic findings that cerebellum and its outflow are the key structures in ET and degeneration of gray matter in cerebellum is followed by consequent wallerian degeneration of white matter (WM) fibers, the aim of the present study was to investigate changes in anisotropy in patients with ET.

MATERIALS AND METHODS

Fractional anisotropy (FA) images were generated from DTI data acquired at 1.5T in 10 patients with ET compared with 8 control subjects by using statistical parametric mapping to make voxel-by-voxel comparisons.

RESULTS

Compared with the control subjects, the patients with ET exhibited significantly reduced FA (P(uncorrected) < .005) in the anterolateral portion of the right pons and decreased FA in the bilateral cerebellum, left retrorubral area of the midbrain, and bilateral deep WM, including the orbitofrontal, lateral frontal, parietal, and temporal WM.

CONCLUSION

This study demonstrates that structural changes in the WM are extensive in patients with ET, supporting the findings of previous functional neuroimaging and pathologic studies.

Pathologic staging of papillary carcinoma of the thyroid with airway invasion based on the anatomic manner of extension to the trachea: a clinicopathologic study based on 22 patients who underwent thyroidectomy and airway resection

We received the clinical and pathologic features of 22 cases of papillary carcinoma of the thyroid that invaded the trachea and were treated by thyroidectomy and airway resection with or without reconstructive surgery over an interval of 16 years. We studied the fine relationships between lamina propria and lymphatics in the region between the isthmus of the thyroid and the trachea. The manner of invasion of papillary carcinoma of the thyroid was by blunt dissection along blood vessels and collagen fibers oriented perpendicularly to the tracheal lumen between cartilaginous rings. Although lymph node metastases were found in 14 patients (64%), we observed lymphangitic tumor in the tracheal mucosa in only three patients (14%). We devised a staging system for papillary carcinoma of the thyroid based on the extent of invasion of the trachea. Of the 11 patients with stage I, II, or III disease, none of six (0%) followed for 5 years died of thyroid cancer in the 5-year observation period; one patient in this group died later of thyroid cancer. Of the 11 patients with stage IV disease, five of seven (71%) followed for 5 years died of thyroid cancer in the 5-year observation period; one additional patient in this group died later of thyroid cancer.

Purification and characterization of the heat shock proteins HslV and HslU that form a new ATP-dependent protease in Escherichia coli

The hslVU operon in Escherichia coli encodes two heat shock proteins, HslV, a 19-kDa protein homologous to beta-type subunits of the 20 S proteasomes, and HslU, a 50-kDa protein related to the ATPase ClpX. We have recently shown that HslV and HslU can function together as a novel ATP-dependent protease, the HslVU protease. We have now purified both proteins to apparent homogeneity from extracts of E. coli carrying the hslVU operon on a multicopy plasmid. HslU by itself cleaved ATP, and pure HslV is a weak peptidase degrading certain hydrophobic peptides. HslU dramatically stimulated peptide hydrolysis by HslV when ATP is present. With a 1:4 molar ratio of HslV to HslU, approximately a 200-fold increase in peptide hydrolysis was observed. HslV stimulated the ATPase activity of HslU 2-4-fold, but had little influence on the affinity of HslU to ATP. The nonhydrolyzable ATP analog, beta,gamma-methylene-ATP, did not support peptide hydrolysis. Other nucleotides (CTP, dATP) that were slowly hydrolyzed by HslU allowed some peptide hydrolysis. Therefore, ATP cleavage appears essential for the HslV activity. Upon gel filtration on a Sephacryl S-300 column, HslV behaved as a 250-kDa oligomer (i.e. 12-14 subunits), and HslU behaved as a 100-kDa protein (i.e. a dimer) in the absence of ATP, but as a 450-kDa multimer (8-10 subunits) in its presence. Therefore ATP appears necessary for oligomerization of HslU. Thus the HslVU protease appears to be a two-component protease in which HslV harbors the peptidase activity, while HslU provides an essential ATPase activity.

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.

Analysis of reliability indices from Humphrey visual field tests in an urban glaucoma population

PURPOSE

Visual field assessment is extremely important in glaucoma management, but interpretation is affected by the quality of the patient's performance. The authors have investigated the reliability of visual field performance by a randomly selected sample of the chronic glaucoma population at an urban tertiary care practice.

METHODS

Patient reliability in Humphrey automated visual field testing was studied in 106 randomly selected chronic open-angle glaucoma patient charts, which provided 768 tests (mean, 7.2 +/- 4.8 fields; range, 2-18 fields). Reliability criteria were established as less than 20% fixation losses, less than 33% false-negative error, and less than 33% false-positive error, as recommended by Humphrey Instruments, Inc (San Leandro, CA).

RESULTS

Patients performed reliably in 61% of right eye fields, 58% of left eye fields, and 59.5% overall. Of the 106 patients, only 35 (33%) were always reliable in both eyes, whereas 8 (7.5%) were always unreliable in both eyes. The most common cause of unreliability was fixation loss (39%), whereas false-positive error (5%) and false-negative error (9%) were less frequent. A more severely depressed mean deviation correlated significantly with poorer performance on the three reliability indices, with false-negative error having the greatest correlation, followed by fixation loss and false-positive error. Corrected pattern standard deviation correlated closely only with false-negative error. Prolonged test time also correlated with all three reliability indices. Age was a significant factor for fixation loss but not for false-negative or false-positive error.

CONCLUSIONS

The authors conclude that fewer than two thirds of the Humphrey visual fields were reliable with the authors' urban tertiary care population of patients with glaucoma. Relaxing the fixation loss criterion to less than 33% improved the rate of reliability to approximately 75%. The severity of glaucomatous visual field defects, test time, and age were identified as factors influencing the reliability of the Humphrey visual fields.

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.

Cyclin D1 overexpression is an indicator of poor prognosis in resectable non-small cell lung cancer

Cyclin D1 is one of the G1 cyclins that control cell cycle progression by allowing G1 to S transition. Overexpression of cyclin D1 has been postulated to play an important role in the development of human cancers. We have investigated the correlation between cyclin D1 overexpression and known clinicopathological factors and also its prognostic implication on resected non-small-cell lung cancer (NSCLC) patients. Formalin-fixed and paraffin-embedded tumour tissues resected from 69 NSCLC patients between stages I and IIIa were immunohistochemically examined to detect altered cyclin D1 expression. Twenty-four cases (34.8%) revealed positive immunoreactivity for cyclin D1. Cyclin D1 overexpression is significantly higher in patients with lymph node metastasis (50.0% vs 14.4%, P = 0.002) and with advanced pathological stages (I, 10%; II, 53.8%; IIIa, 41.7%, P = 0.048; stage I vs II, IIIa, P = 0.006). Twenty-four patients with cyclin D1-positive immunoreactivity revealed a significantly shorter overall survival than the patients with negativity (24.0 +/- 3.9 months vs 50.1 +/- 6.4 months, P = 0.0299). Among 33 patients between stages I and II, nine patients with cyclin D1-positive immunoreactivity had a much shorter overall survival (29.7 +/- 6.1 months vs 74.6 +/- 8.6 months, P = 0.0066). These results suggest that cyclin D1 overexpression is involved in tumorigenesis of NSCLCs from early stage and could be a predictive molecular marker for poor prognosis in resectable NSCLC patients, which may help us to choose proper therapeutic modalities after resection of the tumor.