Risk factor analysis and nomogram construction in patients with distant metastatic prostate cancer at different PSA levels: a study based on the SEER database.

OBJECTIVE: Prostate cancer (PCa) is the most common malignant tumor in the male genitourinary system. Once PCa has metastasized, it is very difficult to cure. The purpose of this study was to investigate the prognostic risk factor analysis of patients with different prostate-specific antigen (PSA) levels in distant metastatic PCa. At the same time, we construct effective models for predicting the survival rate of prostate cancer patients. PATIENTS AND METHODS: Data on prostate cancer patients with the presence of distant metastases were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. PCa patients with distant metastases were categorized into two groups based on PSA levels, one with PSA <20 ng/mL and the other with PSA ≥20 ng/mL. Univariate and multivariate COX regression analyses were used to identify independent factors affecting the prognosis of the patients. A nomogram was constructed using the independent prognostic factors, and the results were evaluated using calibration curves, timeROC curves, and Kaplan-Meier curves. RESULTS: In the PSA <20 ng/mL group, there were a total of 1,832 patients. COX regression analysis showed that age, marital status, N stage, grade, Gleason score, and medical household income inflation were independent prognostic factors for overall survival (OS) in patients. In addition, we found that age, marital status, N stage, bone metastasis, grade, and Gleason score were independent prognostic factors for cancer-specific survival (CSS) in patients. In the PSA ≥20 ng/mL group, there were a total of 5,314 patients. It was found that age, ethnicity, marital status, bone metastasis, first malignant primary indicator, grade, Gleason score, and medical household income inflation were patients' independent prognostic factors for OS. For CSS, we found that age, ethnicity, marital status, T stage, radiotherapy, bone metastasis, Gleason score, and Median household income inflation were independent prognostic factors. Constructing a nomogram can accurately predict the prognosis of this group of patients. CONCLUSIONS: We found different independent prognostic factors for different PSA levels in patients with distant metastatic PCa. A new nomogram was constructed to predict OS and CSS in patients, which helps in clinical-assisted decision-making.

A comprehensive analysis of essential meiotic endonuclease 1 to prognosis and immune infiltration in kidney renal clear cell carcinoma.

OBJECTIVE: Clear cell renal cell carcinoma (ccRCC) is the most common type of cancer, and its molecular pathogenesis is unclear. In this study, we investigated the prognostic value of essential meiotic endonuclease 1 (EME1) in kidney renal clear cell carcinoma (KIRC). MATERIALS AND METHODS: We downloaded the RNA-Seq expression of 526 KIRC tissues and 72 normal tissues from the TCGA database and the corresponding clinical data. The gene expression profiles associated with four clear cell renal cell carcinomas were downloaded from the GEO database for analysis. The expression of EME1 in clear renal cell carcinoma and its correlation with the clinical baseline data were analyzed. Kaplan-Meier survival curve analysis was performed to assess the relationship between EME1 and patient survival. Enrichment analysis was performed to elucidate the possible functions of EME1. We also analyzed the relationship between the EME1 expression and immune infiltration through TIMER2.0 and TISIDB online databases as well as the relationship between EME1 and common immune checkpoints. RESULTS: EME1 was identified as a risk factor for overall survival in clear cell renal cell carcinoma with a hazard ratio of 3.201 (95% confidence interval: 2.430-4.215; p < 0.001). EME1 was highly expressed in KIRC compared to that in normal tissues (p < 0.001) and in the worse TNM stages and late stages (stage 3/4) (p < 0.001). High EME1 expression was strongly associated with the advanced T stage (p = 0.003), advanced N stage (p = 0.002), and advanced M stage (p = 0.006). Research data on KIRC were simultaneously collected and analyzed from the GEO database, including GSE40435, GSE53000, GSE68417, and GSE53757. EME1 predicted the survival status in KIRC patients (AUC = 0.62). We further established a nomogram including the correlation between the high and low EME1 expression, and EME1 was found to contribute to the prediction of the probability of patient survival with a c-index = 0.796. Kaplan-Meier analysis revealed a lower likelihood of survival with a high EME1 expression (p < 0.001). In addition, further bioinformatics analysis suggested that EME1 may be associated with the extent of immune infiltration in KIRC. CONCLUSIONS: An increased expression of EME1 in KIRC is thus associated with advanced clinicopathological features, possibly acting as a potential biomarker of poor prognosis in KIRC.

[Clinical observation of microsurgical removal of the hemilateral tuberculum sellae meningiomas through contralateral eyebrow arch approach].

The current study aimed to investigate the clinical feasibility of microscopic resection of hemilateral tuberculum sellae meningiomas (TSM) via the contralateral eye brow arch approach. The clinical data of 34 patients with TSM who underwent microsurgery from January 2016 to June 2021 in the Neurosurgery Department of Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine and the First Affiliated Hospital of Henan University were collected and reviewed. The postoperative visual acuity improvement rate was 88.5% (23/26), and the total tumor resection rate was 88.2% (30/34); the postoperative visual acuity improvement in patients with total tumor resection was better than that of patients with partial resection [90.9% (20/22) vs 3/4]. Meanwhile, the postoperative visual acuity improvement in patients with the superior optic nerve and laterl-superior optic nerve was better than that of patients with the lateral optic nerve type (12/14, 8/8 vs 3/4). Supraorbital skin numbness occurred in 3 cases after operation, and the symptoms disappeared during follow-up; 2 cases had mild disturbance of hormone level, and urine output of 2 cases increased after operation, which returned to normal level after symptomatic treatment; 1 case had subcutaneous effusion which was absorbed after treatment. There were no complications such as olfactory disturbance and intracranial infection. During follow-up for 3-60 (33±6) months, recurrence occurred in 2 cases and reoperation was performed. For the hemilateral TSM, according to the preoperative evaluation of the origin of the TSM and the side with visual impairment, the contralateral eyebrow approach is selected to fully expose the tumor base below the optic nerve. It is beneficial to fully resect the tumor under direct vision, and the symptoms of postoperative visual impairment are significantly improved, indicating that the current surgical method can be used in the clinical setting.

[The effect of perioperative fluid therapy on early postoperative pulmonary complications after orthotopic liver transplantation].

Objective: To investigate the effect of perioperative fluid therapy on early postoperative pulmonary complication (PPC) after orthotopic liver transplantation (OLT). Methods: The clinical data of 132 patients who underwent OLT in the First Affiliated Hospital of Xi'an Jiaotong University from April 2016 to December 2017 were analyzed retrospectively. These patients included 96 males and 36 females, aged (47.3±9.6) years (range: 24-69 years). Based on the clinical manifestations, laboratory and imaging findings of patients in ICU and PPC occurrence within 7 days after OLT surgery, the patients were divided into 2 groups: non-PPC group and PPC group. Univariate and multivariate logistic regression analyses were used to evaluate the association between perioperative variables and PPC. The Kaplan-Meier method was used to estimate cumulative survival of recipients with or without PPC within 2-years. Results: During the follow-up, 11 patients (8.3%) died and 72 patients (54.5%) developed PPC after operation. There were 34 cases, 6 cases, 3 cases, 4 cases, 15 cases, 6 cases and 4 cases of only pleural effusion, only pulmonary edema, only pneumonia, pleural effusion with pneumonia, pleural effusion with pulmonary edema, pleural effusion with atelectasis, and pleural effusion with pneumonia and pneumonia in PPC, respectively. Univariate analysis showed that the preoperative factors (model for end-stage liver disease score), the intra-operative factors (duration of surgery, total infusion volume, total blood products) and the postoperative cumulative fluid balance within the first 24 h, 48 h, and 72 h were the prognosis factors of PPC (P<0.05). At least two out of the first three postoperative days with a fluid balance of ≤-500 ml was a protective factor. Using multivariate analysis by Logistic regression, only the red blood units >10 U (OR=3.55, 95% CI: 1.35-9.26, P=0.010) and the cumulative fluid intake >12 L (OR=2.98, 95% CI: 1.14-7.80, P=0.026) within the first 72 h after operation were independent prognosis factors of PPC after OLT. Kaplan-Meier analysis showed that the cumulative survival rate was lower in PPC group than that in non-PPC group (χ(2)=6.590, P=0.01). Conclusion: Massive red blood cell transfusion and the cumulative fluid volume >12 L during perioperative 72 hours are independent prognosis factors of PPC after OLT.

[The evaluation of severity and treatment for OSAHS by acoustic pharyngometry which in different postures].

Objective: To investigate the optimal position in application of acoustic pharyngometry to detect the pharyngeal condition and to assess its therapeutic effect on obstructive sleep apnea hypopnea syndrome(OSAHS). Method: Eight adult males were assigned to the normal group, and 57 male patients with OSAHS diagnosed by polysomnograhy(PSG) were assigned to the snoring group. Of the snoring group, 11 patients who were diagnosed severe OSAHS underwent low-temperature plasma uvulopaltopharyngoplasty(UPPP) and coblationchanneling of the tongue(CCT), were assigned to the operation subgroup; 8 patients underwent continuous positive airway pressure(CPAP), which was assigned to the CPAP subgroup. And remainders underwent conservative treatment, including weight loss and position change. Acoustic pharyngometry (three positions including sitting position, supine position and lateral position) and PSG exam were performed in all participants. Additionally, acoustic pharyngometry under three positions was conducted again in patients in the operation and CPAP subgroups three months after treatment. Result: The minimum cross-sectional area was negatively associated with both AHI and the percentage of time with oxygen saturation below 90%(SIT90)( P<0.01). The correlation coefficient of the minimum crosssectional area insupine position with AHI and SIT90 were r=-0.569,r=-0.478, respectively. Under supine position, the minimum crosssectional area was negatively correlated with body mass index(BMI)(r=-0.265, P=0.033), and the minimum crosssectional area was negatively associated with neck circumference(r=-0.309, P=0.012). The minimum cross-sectional area was significantly increased after treatment of OSAHS(both operation and CPAP), which was statistically different before and after treatment compared to the control group(P<0.01). Conclusion: ①The minimum cross-sectional area is significantly correlated with AHI and SIT90, respectively. The acoustic pharyngometry can be used to screen OSAHS patients. ②In this study, the minimum cross-sectional area under supine position is significantly smaller than that under sitting position. In addition, the minimum cross-sectional area under supine position harbored a better correlation with AHI and SIT90, which could better reflect the narrowness of pharyngeal cavity during sleep. ③Acoustic pharyngometry could be a simple, rapid and non-invasive technique that can objectively evaluate the efficacy of surgical and CPAP methods, and provided a more favorable basis for future clinical work..

[The test of KIM-1, Cys C and ß2-MG to assess the early renal damage in OSAHS patients and its clinical significance].

Objective:The purpose of this study was to investigate the expression level of kidney injury molecule l (KIM-1), cystatin C (Cys C) and ß2-microglobulin (ß2-MG) in patients with obstructive sleep apnea and hypopnea syndrome (OSAHS) disease, and to assess the clinical significance among these factors in OSAHS patients with early renal injury.Method:Total 80 OSAHS patients diagnosed by polysomnogram (PSG) in the sleep disorder lab were selected as experimental group and 15 healthy adults who were normal in PSG examinations were selected as control group. Measure the levels of Cys C, ß2-MG in fasting venous blood in the morning and detecte the level of KIM-1 in midpiece urine after centrifugation by enzyme-linked immunolsorbent assay (ELISA). All data were analyzed by the SPSS13.0 statistical software.Result:①According to AHI grouping: the average levels of uric KIM-1 in the moderate and severe patients were higher than healthy control group (P< 0.01). The serum levels of Cys C and ß2-MG in severe OSAHS patients were higher than healthy control group (P< 0.01). Besides, the difference of the average levels of uric KIM-1 among the mild, moderate and severe OSAHS patients was statistically significant (P< 0.01) and the serum level of Cys C and ß2-MG only in severe OSAHS patients were higher than mild and moderate OSAHS patients (P< 0.01). ②According to LSaO2 grouping: the average level of KIM-1, Cys C and ß2-MG in the severe group were higher than normal control group (P< 0.01). Besides, the average level of KIM-1, Cys C and ß2-MG in severe group were higher than mild and moderate groups (P< 0.01). ③KIM-1, Cys C and ß2-MG were positive correlated with each other and AHI (P< 0.01). ④KIM-1, Cys C and ß2-MG were negative correlated with LSaO2 (P< 0.01). Conclusion:The urine level of KIM-1 might be a sensitive indicator in OSAHS patients with early renal damage. It was better to evaluate renal injury by AHI grouping than LSaO2 in OSAHS patients.

Enhanced ultraviolet emission from Au/Ag-nanoparticles@MgO/ZnO heterostructure light-emitting diodes: A combined effect of exciton- and photon- localized surface plasmon couplings.

Localized surface plasmon (LSP)-enhanced ultraviolet light-emitting diodes (LEDs) based on a Au/MgO/ZnO metal/insulator/semi- conductor heterostructure were fabricated by embedding Ag nanoparticles (Ag-NPs) into MgO dielectric layer. A ~6-fold electroluminescence (EL) enhancement was achieved from the Ag-NPs decorated device. Time-resolved spectroscopy studies, as well as analogue simulation and theoretical estimation based on experimental data, reveal that the internal quantum efficiency and light extraction efficiency of the heterojunction LED are increased ~3-fold and ~2-fold, respectively, as a result of the introduction of Ag LSPs. This result indicates that the observed EL enhancement originates from a combined effect of both exciton-LSP coupling and photon-LSP coupling.

Efficacy of drug-eluting stent for chronic total coronary occlusions at different follow-up duration: a systematic review and meta-analysis.

OBJECTIVE: DESs have been proved to be beneficial for patients with chronic total coronary occlusions (CTO) in terms of cardiac function and other prognosis. We aim to compare the efficacy and safety of drug-eluting stent (DES) and bare-metal stent (BMS) in CTO recanalization at different follow-up duration. METHODS: Articles comparing outcomes between DES and BMS implantation in patients with CTO was searched. A fixed-effect (inverse-variance weighted) and random-effect (DerSimonian and Laird) model were used to analyze the pooling results. RESULTS: A total of 29 comparative studies including 24 cohort studies and 5 randomized controlled studies were identified with a total of 9140 patients (5008 received BMS and 4132 received DES). The risk of all cause death for DES was higher at 6 months and lower at 12 months than BMS, and no significant difference was shown at 24, 36 and 60 months. DES group had lower risk of MI after 12 months implantation, and no difference was shown at 6, 24, 36 and 60 months. Major adverse cardiovascular event (MACE)-free survival was clinically and significantly improved by 73%, 68%, 49%, 40% and 37% respectively in DES group at 6,12, 24, 36, and 60 months. CONCLUSIONS: DES is superior to BMS in binary restenosis, reocclusion and MACE-free survival during long-term follow up. The occurrences of all-cause death and MI show that the risk rate of BMS is higher than that of DES at 12 months. The frequency of all-cause death of DES is higher than BMS at 6 months. DES has higher risk of in-stent thrombosis than BMS at 36 months of implantation.

Artificial pneumothorax in CT-guided radioactive iodine-125 seed implantation in the treatment of mediastinal tumors.

OBJECTIVE: To explore the efficacy and safety of CT-guided radioactive Iodine-125 seed implantation in treating mediastinal tumors in the thorax with artificial pneumothorax. PATIENTS AND METHODS: Artificial pneumothorax was created using the 22 G thoracic puncture needle in 36 patients with mediastinal tumors, followed by CT-guided radioactive Iodine-125 seed implantation. An equal volume of gas was extracted after the treatment. RESULTS: The treatment was completed in 35 patients. The tumor target volumes for the radiation treatment were not significantly different before and after the artificial pneumothorax (p = 0.265). No severe complications such as refractory pneumothorax, hemoptysis, or diffuse hemorrhage in the implantation area was observed. CONCLUSIONS: Artificial pneumothorax can reduce the CT image interference caused by the needle tract bleeding during the radioactive Iodine-125 implantation.

ZnO ultraviolet random laser diode on metal copper substrate.

Direct fabrication of light emitting devices on metal substrates is highly desirable due to their advantages of high thermal conductivity and light reflection. In this work, we demonstrated a feasibility of directly fabricating ZnO-based ultraviolet laser diodes on metal substrates. By introducing an anti-oxidation buffer layer, Au/MgO/ZnO metal-insulator-semiconductor heterojunction devices are successfully fabricated on the copper substrate. Electrically pumped ultraviolet random lasing was achieved from ZnO active layer. The use of copper substrate offers some merits, including lower thermal effect and higher stability of emission wavelength.

Performance improvement of resistive switching memory achieved by enhancing local-electric-field near electromigrated Ag-nanoclusters.

By introducing Ag nanoclusters (NCs), ZnO-based resistive switching memory devices offer improved performance, including improved uniformity of switching parameters, and increased switching speed with excellent reliability. These Ag NCs are formed between the top-electrode (cathode) and the switching layer by an electromigration process in the initial several switching cycles. The electric field can be enhanced around Ag NCs due to their high surface curvature. The enhanced local-electric-field (LEF) results in (1) the localization of the switching site near Ag NCs, where oxygen-vacancy-based conducting filaments have a simple structure, and tend to connect Ag NCs along the LEF direction; (2) an increase in migration and recombination rates of oxygen ions and oxygen vacancies. These factors are responsible for the improvement in device performance.

Clinical and prognostic significance of protocadherin-10 (PCDH10) promoter methylation in bladder cancer.

OBJECTIVE: To investigate the clinical and prognostic significance of protocadherin-10 (PCDH10) promoter methylation in serum-derived DNA from patients with bladder cancer. METHODS: PCDH10 promoter methylation status was determined using methylation-specific polymerase chain reaction of DNA extracted from serum of patients with bladder cancer, and age- and sex-matched controls. Clinical and pathological details of bladder cancer were recorded. RESULTS: PCDH10 promoter methylation was detected in 59/117 (50.4%) of patients with bladder cancer, and none of 37 (0%) controls. Methylation was significantly associated with advanced stage (T(2)-T(4)), high grade (G(3)), tumour recurrence and larger tumour size (> 3 cm). In addition, methylation was associated with significantly worse survival and was an independent predictor of overall survival. CONCLUSION: Serum-based analysis of PCDH10 promoter methylation may represent a useful noninvasive biomarker of malignant behaviour and outcome in bladder cancer.

A high-resolution comparative map of porcine chromosome 4 (SSC4).

We used the IMNpRH2(12,000-rad) RH and IMpRH(7,000-rad) panels to integrate 2019 transcriptome (RNA-seq)-generated contigs with markers from the porcine genetic and radiation hybrid (RH) maps and bacterial artificial chromosome finger-printed contigs, into 1) parallel framework maps (LOD ≥ 10) on both panels for swine chromosome (SSC) 4, and 2) a high-resolution comparative map of SSC4, thus and human chromosomes (HSA) 1 and 8. A total of 573 loci were anchored and ordered on SSC4 closing gaps identified in the porcine sequence assembly Sscrofa9. Alignment of the SSC4 RH with the genetic map identified five microsatellites incorrectly mapped around the centromeric region in the genetic map. Further alignment of the RH and comparative maps with the genome sequence identified four additional regions of discrepancy that are also suggestive of errors in assembly, three of which were resolved through conserved synteny with blocks on HSA1 and HSA8.

Clinical significance of CDH13 promoter methylation in serum samples from patients with bladder transitional cell carcinoma.

H-cadherin (CDH13; also known as T-cadherin), which functions as a tumour suppressor, is frequently silenced by promoter methylation in human cancers including bladder transitional cell carcinoma (TCC). This study investigated the clinical significance of methylation of the CDH13 gene promoter in serum from patients with bladder TCC. Methylation status of CDH13 in serum samples from 127 patients with primary bladder TCC and 41 healthy volunteers (controls) was examined by methylation-specific polymerase chain reaction. CDH13 methylation was found in 39 patients with bladder TCC (30.7%) but in no controls. CDH13 methylation was significantly associated with advanced tumour stage, high-grade tumour, large tumour size, tumour recurrence and poor prognosis. The results suggested that CDH13 methylation in serum may be a potential predictive biomarker for malignancy in bladder TCC, and an independent pretherapeutic predictor of outcome. Demonstration of CDH13 methylation in serum may facilitate in the prediction of which patients require more aggressive additional post-operative systemic therapy.

PKB/Akt promotes DSB repair in cancer cells through upregulating Mre11 expression following ionizing radiation.

An elevated DNA-repair capacity in cancer cells leads to radiation resistance and severely limits the efficacy of radiation therapy. Activation of Akt is tightly associated with resistance to radiotherapy, and Mre11 protein has important role during the repair of DNA double-strand breaks (DSBs). In this report, our results showed that inhibition of Akt activity impaired the repair of DSBs in CNE2 cells, whereas activated Akt promoted the repair of DSBs in HeLa cells. Knockdown of Mre11 also impaired the process of DSB repair in both these two cell lines. More importantly, we found that Akt could regulate Mre11 expression. Inhibition of Akt activity by small interfering RNA or LY294002 efficiently downregulated the Mre11 expression in CNE2 cells, and transfection with myr-Akt plasmid in HeLa cells upregulated the Mre11 expression. In addition, luciferase reporter analysis revealed that Mre11 reporter activity increased after transfection with myr-Akt1 plasmids, and this myr-Akt1-induced transcriptional activity was blocked in the presence of LY294002. Further study showed GSK3ß/ß-catenin/LEF-1 pathway was involved in this regulation. Knockdown of ß-catenin or LEF-1 led to the downregulation of Mre11, whereas overexpression of ß-catenin led to upregulation of Mre11. The chromatin immunoprecipitation assay assay showed ß-catenin/LEF-1 heterodimer could directly bind to the promoter of Mre11 in vivo. And the luciferase activity of the pGL3-Mre11 and pGL3-Lef increased in HeLa cells following ß-catenin plasmid co-transfected, but was abolished when the LEF-1-binding conserved sequences of Mre11 promoter were mutated. These results together support Akt can upregulate the expression of Mre11 through GSK3ß/ ß-catenin/LEF pathway to elevate DSB-repair capacity in cancer cells.

Photoluminescence of ZnO nanocrystals embedded in BaF2 matrices by magnetron sputtering.

This paper describes ZnO nanocrystals embedded in BaF2 matrices by the magnetron sputtering method in an attempt to use fluoride as a shell layer to embed ZnO nanocrystals core. BaF2 is a wide-band gap material, and can confine carriers in the ZnO films. As a result, the exciton emission intensity should be enhanced. The sample was annealed at 773 K, and X-ray diffraction (XRD) results showed that ZnO nanocrystals with wurtzite structure were embedded in BaF2 matrices. Raman-scattering spectra also confirmed the formation of ZnO nanoparticles. Abnormal longitudinal-optical (LO) phonon-dominant multiphonon Raman scattering was observed in the sample. Room-temperature photoluminescence (PL) spectra showed an ultraviolet emission peak at 374 nm. The origin of the ultraviolet emission is discussed here with the help of temperature-dependent PL spectra. The ultraviolet emission band was a mixture of free exciton and bound exciton recombination observed in the low temperature PL spectra (at 77 K). Abnormal temperature dependence of ultraviolet near-band-edge emission-integrated intensity of the sample was observed. The band tail state was observed in the absorption spectra, illustrating that the impurity-related defects were caused by the shell of the BaF2 grain layer. For comparison, ZnO films on BaF2 substrates were also fabricated by the magnetron sputtering method, and the same measurement methods were used.

Porphyrin interactions with wild-type and mutant mouse ferrochelatase.

Ferrochelatase (EC 4.99.1.1), the terminal enzyme of the heme biosynthetic pathway, catalyzes Fe(2+) chelation into protoporphyrin IX. Resonance Raman and UV-vis absorption spectroscopies of wild-type and engineered variants of murine ferrochelatase were used to examine the proposed structural mechanism for iron insertion into porphyrin. The recombinant variants (i.e., H207N and E287Q) are enzymes in which the conserved amino acids histidine-207 and glutamate-287 of murine ferrochelatase were substituted with asparagine and glutamine, respectively. Both of these residues are at the active site of the enzyme as deduced from the Bacillus subtilis ferrochelatase three-dimensional structure. On the basis of changes in the UV-vis absorption spectrum, addition of free-base or metalated porphyrins to wild-type ferrochelatase and H207N variant yields a 1:1 complex, most likely a monomeric protein-bound species at the active site. In contrast, the addition of porphyrin (either free base or metalated) to E287Q is substoichiometric, as this variant retains bound porphyrin in the active site during isolation and purification. The specificity of porphyrin binding is confirmed by the narrowing of the structure-sensitive lines and the vinyl vibrational mode in the resonance Raman spectra. Shifts in the resonance Raman lines of free-base and metalated porphyrins bound to the wild-type ferrochelatase indicate a nonplanar distortion of the porphyrin macrocycle. However, the magnitude of the distortion cannot be determined without first defining the specific type of deformation. Significantly, the extent of the nonplanar distortion varies in the case of H207N- and E287Q-bound porphyrins. In fact, resonance Raman spectral decompositions indicate a homogeneous ruffled deformation for the nickel protoporphyrin bound to the wild-type ferrochelatase, whereas both planar and ruffled conformations are present for the H207N-bound porphyrin. Perhaps more revealing is the unusual resonance Raman spectrum of the endogenous E287Q-bound porphyrin, which has the structure-sensitive lines greatly upshifted relative to those of the free-base protoporphyrin in solution. This could be interpreted as an equilibrium between protein conformers, one of which favors a highly distorted porphyrin macrocycle. Taken together, these findings suggest that distortion occurs in murine ferrochelatase for some porphyrins, even without metal binding, which is apparently required for the yeast ferrochelatase.

A miniaturized applanation tonometer.

A miniaturized hand-held applanation tonometer is introduced, in which a special cone prism is employed to be an applanation probe to flatten the eye vertically. The self-weight of the probe is just the applanation force, and the applanation area of the ocular cornea is monitored by the optoelectronic signal. The preliminary test demonstrates its good clinical acceptance and its accuracy meeting clinical needs.

The quantum mixed-spin heme state of barley peroxidase: A paradigm for class III peroxidases.

Electronic absorption and resonance Raman (RR) spectra of the ferric form of barley grain peroxidase (BP 1) at various pH values, at both room temperature and 20 K, are reported, together with electron paramagnetic resonance spectra at 10 K. The ferrous forms and the ferric complex with fluoride have also been studied. A quantum mechanically mixed-spin (QS) state has been identified. The QS heme species coexists with 6- and 5-cHS hemes; the relative populations of these three spin states are found to be dependent on pH and temperature. However, the QS species remains in all cases the dominant heme spin species. Barley peroxidase appears to be further characterized by a splitting of the two vinyl stretching modes, indicating that the vinyl groups are differently conjugated with the porphyrin. An analysis of the currently available spectroscopic data for proteins from all three peroxidase classes suggests that the simultaneous occurrence of the QS heme state as well as the splitting of the two vinyl stretching modes is confined to class III enzymes. The former point is discussed in terms of the possible influences of heme deformations on heme spin state. It is found that moderate saddling alone is probably not enough to cause the QS state, although some saddling may be necessary for the QS state.

Resonance Raman investigation of nickel microperoxidase-11.

Resonance Raman and UV-visible absorption spectra show that nickel(II) microperoxidase-11 (NiMP-11) is four-coordinate in aqueous solution in the pH range from 1.0 to 13.0. In aqueous solutions of NiMP-11 in the absence of cetyltrimethylammonium bromide (CTAB), NiMP-11 is aggregated. In CTAB micellar solutions, where aggregation of NiMP-11 does not occur, the Raman spectra of NiMP-11 are similar to that of nickel(II) cytochrome c (NiCyt-c). The presence of the peptide segment shifts the equilibrium heavily in favor of the nonplanar form, just as does the entire protein component in the case of NiCyt-c. This further elucidates the structural mechanism by which the protein segment ruffles the heme, most likely modulating the redox potential as indicated for the cytochromes c3 [Ma, J.-G., et al. (1998) Biochemistry 37, 12431-12442]. Furthermore, the hydrophobic environment that is provided by the CTAB micelle is found to be crucial to the native folding of the pentapeptide and formation of two hydrogen bonds in the peptide backbone. These two H-bonds act to contract the peptide segment exerting the force on the macrocycle that causes the ruffling and makes the redox potential more negative than if the heme were to remain planar. The structure of the heme and pentapeptide may also be associated with redox-linked triggering of the formation and release of cytochrome-protein complexes.