[Etiological analysis on a foodborne disease outbreak caused by two serotypes of Salmonella].

Objective: To understand the etiological characteristics of 2 serotypes of Salmonella strains isolated from a foodborne disease outbreak. Methods: A total of 11 anal swabs of the cases, 13 suspected contaminated food and 10 environmental samples were collected from a foodborne disease outbreak occurred on September 8, 2022 in a school. The anal swabs were enriched with selenite brilliant green enrichment broth (SBG) and brain heart infusion broth (BHI) respectively. PCR detection and culture of common intestinal pathogens were carried out. The suspected food samples were tested according to national standards for food safety. Multiple suspected Salmonella colonies were obtained and selected for serotype determination and whole genome sequencing. Serotypes were determined based on the whole-genome sequence, and clustering analysis was performed based on core genome single nucleotide polymorphism (SNP). Results: The positive rates of Salmonella in anal swabs and suspected food samples were 9/11 and 5/13 respectively. Both Salmonella Uganda and Salmonella Idikan were isolated from 4 anal swabs and 4 suspected food samples. For the remaining samples, only Salmonella Uganda or Salmonella Idikan was isolated in each sample. The positive rate of Salmonella in 11 anal swabs of the cases after BHI enrichment for 12 h and 24 h were all 9/11 in real-time PCR, same to the culture results. Salmonella Uganda and Salmonella Idikan formed two independent and genetically distant lineages in the clustering tree based on core genome SNP, and 0-14 and 0-23 SNP were observed in Salmonella Uganda and Salmonella Idikan respectively. Conclusions: This foodborne disease outbreak was probably caused by Salmonella Uganda and Salmonella Idikan, which both exhibited strong genetic diversity. The PCR based pathogen screening strategy plus pathogen enrichment for cases' annal swabs can be used in the routine outbreak investigation.

Auto interpretable depth learning model to analyze the hemodynamic changes and pulmonary complications in laparoscopic gynecologic tumor surgery with nalmefene hydrochloride combined with general anesthesia.

OBJECTIVE: In this work, based on intelligent computing, the biological signals of patients were analyzed to investigate the hemodynamic changes and pulmonary complications of Nalmefene Hcl combined with general anesthesia (GA) in laparoscopic gynecological tumor surgery (GTS). PATIENTS AND METHODS: Eighty computer-aided GTS patients were randomly divided into a control group (n = 40) and an observation group (n = 40). Biomedical electrocardiogram (ECG) signals were detected by wavelet neural network in all patients undergoing laparoscopic gynecological tumor surgery and were computerized according to the android interface definition language model (AIDL). GA was used during surgery. The observation group was injected intravenously with 0.2 µg/kg naproxenacin hydrochloride after operation. The control group was given 1 mL 0.9% sodium chloride solution after operation. Mean arterial pressure (MAP), heart rate (HR), respiratory rate (RR), pulse oxygen saturation (SPO), coma score, and adverse reactions (AR) were compared between the two groups at 10, 20, and 30 minutes after wakefulness. The hemodynamic parameters between the two groups were compared. Serum urocholine (URO) and creatinine (Cre) levels were analyzed in patients without complications. RESULTS: ECG waveform based on wavelet neural network has a high recognition rate and strong generalization ability. 37 patients in the observation group recovered within 10 minutes after surgery, and the recovery rate at 30 minutes was 95%. 30 patients in the control group awoke 10 minutes after the operation, and the recovery rate at 30 minutes m-AR was 75%. The average abstract windows toolkit (AWT) of the observation group and control group was 11.87 ± 5.78 min and 16.46 ± 5.32 min, respectively, and the difference was significant (p < 0.05). There were significant differences in HR, systolic blood pressure (SBP), and diastolic blood pressure (DBP) between the observation group and the control group during the extubation (p < 0.05). Blood gas indexes PaO2, PvO2, PaCO2, and PvCO2 in the observation group were significantly different from those in the control group half an hour after the operation and half an hour after pneumoperitoneum (p > 0.05). CONCLUSIONS: Intelligent computational biological signal detection was beneficial to the development of surgery. Nalmefene Hcl combined with GA on the basis of the AIDL model has a significant effect on the awakening of GTS patients and can shorten sleep time. Patients with underlying cardiac disease were more likely to develop postoperative lung complications.

Comparison of laparoscopic common bile duct exploration and endoscopic retrograde cholangiopancreatography combined with laparoscopic cholecystectomy for patients with gallbladder and common bile duct stones a meta-analysis of randomized controlled trials.

OBJECTIVE: This study aimed to compare the efficacy and safety of laparoscopic common bile duct exploration (LCBDE) and endoscopic retrograde cholangiopancreatography (ERCP) combined with laparoscopic cholecystectomy (LC) to determine which one provides a better outcome for patients with gallbladder and common bile duct stones. MATERIALS AND METHODS: An electronic literature search was undertaken using Embase, Medline, PubMed, and Cochrane Library databases up to April 2022. For quality assessment of included studies, randomized controlled trials (RCTs) were assessed by utilizing the Jadad scale. The primary outcome includes surgical success rate, retained stone rate, stone clearance rate, major morbidity, and mortality. The second outcome includes conversion to open surgery rate, postoperative pancreatitis, bile leakage, cholangitis, hemorrhage, pneumonia, and surgical-site infection. RESULTS: 14 randomized controlled trials with 2,181 patients were included. No significant difference was seen between the two groups in terms of surgical success, stone clearance, retained stones, operation time, and total morbidity. LC-LCBDE had higher rate of bile leakage [relative risk (RR): 4.52; 95% confidence interval (CI): 2.19-9.31] and lower rate of postoperative pancreatitis (RR: 0.25; 95% CI: 0.13-0.46), cholangitis (RR: 0.17; 95% CI: 0.05-0.67), and hemorrhage (RR: 0.18; 95% CI: 0.07-0.42). CONCLUSIONS: Both LC+LCBDE and LC+ERCP are safe, effective, and minimal-invasive treatments for concomitant gallbladder and CBD stones. LC-LCBDE was associated with comparable effects compared with LC+ERCP in terms of surgical success rate, stone clearance rate, retained stones rate, operation time, and total morbidity. At the same time, LC-LCBDE had a higher rate of bile leakage and a lower rate of postoperative pancreatitis, cholangitis, and hemorrhage.

Association between Depressive Symptoms and Risk of Sarcopenia in Taiwanese Older Adults.

OBJECTIVES: Symptoms of depression and high risk of sarcopenia are common among the older population; however, the associations between these remain unclear. Thus, the present study identified whether depressive symptoms are associated with older adults' sarcopenia risks. PARTICIPANTS: This nationally representative study in Taiwan investigated the older adult population ( ≥ 65 years) using a telephone survey conducted between 2019 and 2020. DESIGN: Self-reported data obtained included depressive symptoms (5-item from Center for Epidemiological Studies-Depression scale), sarcopenia risks (SARC-F questionnaire), and individual characteristics. The generalized additive models were used to examine the nonlinear associations between depressive symptoms and the risk of sarcopenia. RESULTS: A total of 1,068 older Taiwanese adults (72.15 ± 5.71 years; 52.7% women) participated in the survey. In the unadjusted model, the results showed a significant nonlinear association between high scores on the CES-D and sarcopenia scores (p < .001). Even after adjusting for covariates (sex, age, residential areas, education, marital status, working status, living status, smoking, drinking, and BMI), it still showed a significant non-linear association (p < .001). CONCLUSION: The results indicated that depressive symptoms were nonlinearly related to older adults' sarcopenia risks. Interventions or programs aiming to alleviate depression can be an effective strategy to prevent sarcopenia in the older adult population.

[Homologous modeling and binding ability analysis of Spike protein after point mutation of severe acute respiratory syndrome coronavirus 2 to receptor proteins and potential antiviral drugs].

OBJECTIVE: To explore the natural mutations in Spike protein (S protein) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the changes of affinity between virus and associated receptors or drug molecules before and after the mutation based on whole length sequencing results. METHODS: In the study, the bioinformatics analysis of all the published sequences of SARS-CoV-2 was conducted and thus the high frequency mutation sites were affirmed. Taking advantages of PolyPhen-2, the functional influence of each mutation in S protein was prospected. The 3D homologous modelling was performed by SWISS-MODEL to establish mutated S protein structural model, in which the protein-docking was then implemented with angiotensin-converting enzyme 2 (ACE2), dipeptidyl peptidase-4 (DPP4) and aminopeptidase N (APN) by ZDOCK, and the combining capacity of each mutated S protein evaluated by FiPD. Finally, the binding ability between mutated S proteins and anti-virus drugs were prospected and evaluated through AutoDock-Chimera 1.14. RESULTS: The mutations in specific region of S protein had greater tendency to destroy the S protein function by analysis of mutated S protein structure. Protein-receptor docking analysis between naturally mutated S protein and host receptors showed that, in the case of spontaneous mutation, the binding ability of S protein to ACE2 tended to be weakened, while the binding ability of DPP4 tended to be enhanced, and there was no significant change in the binding ability of APN. According to the computational simulation results of affinity binding between small molecular drugs and S protein, the affinity of aplaviroc with S protein was significantly higher than that of other small molecule drug candidates. CONCLUSION: The region from 400-1 100 amino acid in S protein of SARS-CoV-2 is the mutation sensitive part during natural state, which was more potential to mutate than other part in S protein during natural state. The mutated SARS-CoV-2 might tend to target human cells with DPP4 as a new receptor rather than keep ACE2 as its unique receptor for human infection. At the same time, aplaviroc, which was used for the treatment of human immunodeficiency virus (HIV) infection, may become a new promising treatment for SARS-CoV-2 and could be a potential choice for the development of SARS-CoV-2 drugs.

MiR-204 promotes fracture healing via enhancing cell viability of osteoblasts.

OBJECTIVE: To investigate the effects and related mechanisms of miR-204 on fracture healing. MATERIALS AND METHODS: Mouse osteoblastic cell line MC3T3-E1 was used in our experiment. Three groups were established to investigate the potential function between miR-204 and osteoblastic cells: miR-NC group (negative control), miR-204 mimics group (MC3T3-E1 cells transfected with miR-204 mimics) and miR-204 mimics + inhibitor group (MC3T3-E1 cells transfected with miR-204 mimics and inhibitor). After incubation, cell viability, activity of caspase-3, and migration ability of MC3T3-E1 cells, were measured. Further, the expression levels of Runt-related transcription factor 2 (RUNX2) and Osterix (OSX) were detected and analyzed. RESULTS: Compared with miR-NC group, the cell viability and migration ability of MC3T3-E1 cells were enhanced while the activity of caspase-3 was respectively mitigated. Besides, the expression level of RUNX2 and OSX was increased by treatment of miR-204 mimics. However, these variations of the indicators were reversed by the intervention using miR-204 inhibitor. CONCLUSIONS: We revealed the promotion effect of miR-204 on fracture healing, indicating that miR-204 could be a potential therapeutic target for the treatment of a fracture.

Characteristics and formation of typical winter haze in Handan, one of the most polluted cities in China.

Handan, a city within the North China Plain (NCP) region, is a typical city influenced by regional particulate matter (PM) pollution. One-year hourly semi-continuous observation was carried out in 2015 in Handan with the aim of identifying the chemical composition and variations in PM2.5. Moreover, the concentration of aerosol precursors, meteorological factors, and secondary transformations are considered. The results demonstrate that the annual average PM2.5 concentration in Handan is 122.35µgm-3, approximately 3.5 times higher than the Chinese National Ambient Air Quality Standard (NAAQS) (35µgm-3), and only 12days were below the guideline. As expected, PM concentrations are highest in winter, especially in December. In addition, we measure the concentrations of five species commonly found in PM, nitrate, sulfate, ammonium, inorganic carbon, and organic carbon. Of these, nitrate and sulfate account for the largest proportion of PM2.5; during periods when the PM2.5 concentration was below 400µgm-3, nitrate dominates, while above this concentration, sulfate dominate. This is likely related to the nitrogen and sulfur oxidation ratios, which are in turn, especially the sulfur oxidation ratio, driven by high relative humidity (>60%). In addition, haze events are driven by other meteorological conditions, wind speed and direction, where low wind speeds from the south and southwest enable pollutant accumulation, which are infrequently interspersed with brief periods with high wind speeds that promote pollutant dispersal. Even though Handan is among the ten most polluted cities in China with regard to air pollution, few studies beyond model simulations have analyzed air pollutant concentrations in this city. Therefore, this study makes a significant contribution to understanding air pollution in Handan, which can further be used to improve our understanding of regional pollution in the highly populated North China Plain. These results have implications for the creation of policies and legislation, as well as other pollution control measures.

Transcription factor SPZ1 promotes TWIST-mediated epithelial-mesenchymal transition and oncogenesis in human liver cancer.

The epithelial-mesenchymal transition (EMT) is an important process in the progression of cancer. However, its occurrence and mechanism of regulation are not fully understood. We propose a regulatory pathway in which spermatogenic leucine zipper 1 (SPZ1) promotes EMT through its transactivating ability in increasing TWIST1 expression. We compared the expression of SPZ1 and TWIST1 in specimens of hepatocarcinoma cells (HCCs) and non-HCCs. Expression of SPZ1 exhibited a tumor-specific expression pattern and a high correlation with patients' survival time, tumor size, tumor number and progression stage. Moreover, forced expression and knockdown of SPZ1 in hepatoma cells showed that SPZ1 was able to regulate the cellular proliferation, invasion, and tumorigenic activity in a TWIST1-dependent manner in vitro and in vivo. These data demonstrate that SPZ1, a newly dscribed molecule, transactivates TWIST1 promoters, and that this SPZ1-TWIST axis mediates EMT signaling and exerts significant regulatory effects on tumor oncogenesis.

[Analysis of olfactory dysfunction after endoscopic and microscopic endonasal transsphenoidal surgery for pituitary adenoma].

Objective:To analyze the clinical data of patients with olfactory dysfunction after endoscopic or microscopic endonasal transsphenoidal approach,and to screen out the possible related factors,to guide clinical diagnosis and treatment,and to improve the patients' quality of life.Method:In the retrospective study,we analyze patients' data,and follow up them with telephone,records the olfactory levels before and after surgery. In the prospective study,five odors were applied to test the olfactory function before the surgery,then one week,3 weeks and 6 weeks after that. The results were statistically analyzed.Result:In the retrospective study,olfactory dysfunction occurred in 67.74%,47.37%in MTS group and ETS group. The olfactory disorder had no significant difference (P>0.05) among MTS group and ETS group after surgery. And the analysis of factors showed no significant difference. In the prospective study,there is significant difference between the preoperative results and postoperative results about the operative side and nonoperative side in ETS group and MTS group (P<0.05). In all results,there is no significant difference between operative side and nonoperative side in ETS group and MTS group (P>0.05).Conclusion:There is olfactory dysfunction after transsphenoidal surgery to resect pituitary adenomas. To prepare the nasal condition well preoperatively,protect the nasal structure intraoperatively and aplicate appropriate treatment postoperatively may reduce the incidence of olfactory disorder.

The Lake Clinic - providing primary care to isolated floating villages on the Tonle Sap Lake, Cambodia.

CONTEXT: One of the most isolated areas in South-East Asia is the Tonle Sap Lake region in Cambodia. Scattered throughout the lake are remote fishing villages that are geographically isolated from the rest of the country. ISSUE: Receiving health care at a clinic or hospital often involves a full day of travel from the Tonle Sap Lake region, which is unaffordable for the vast majority of residents. INTERVENTION: The Lake Clinic (TLC) is a non-government organization established in 2007. In 2008, a ship was built that was designed for transport of a medical team and supplies to provide primary care to the fishing villages. Initially the project started with one team serving seven villages. TLC has since expanded to two full teams serving 19 villages. TLC provides adult and pediatric primary care, vaccinations, dental services, eyecare services, antenatal care and health education free of charge. From 2008 to 2012, there were a total of 13 160 pediatric visits and 17 722 adult visits. In addition to these services, 739 patients received dental care, 346 patients received eye care, there were 1239 antenatal visits, 116 family planning visits, and 1600 patients received health education. In total, 130 patients were referred to hospitals or health centers for a higher level of care. A total of 6627 immunizations were provided. The most common pediatric illness was upper respiratory infection (44.4%), and the most common adult illness observed was gastritis (20.6%). LESSONS LEARNED: Despite the challenges, TLC has been able to achieve a significant goal: to provide primary care medical services to a remote area of Cambodia where no medical services were previously available. TLC strives to strengthen healthcare delivery with the goal to provide the best possible care in the region. New partnerships have allowed laboratory capacity and a formalized hospital referral system for pediatric patients beginning in 2014. A new boat, which completed construction in December 2013 and is now fully operational, has allowed the TLC team to reach a greater number of patients more efficiently.

Functional interaction of Ugene and EBV infection mediates tumorigenic effects.

Epstein-Barr virus (EBV) infection is associated with many human neoplasms, in which EBV-derived latent membrane protein-1 (LMP1) appears to be critical, but its exact oncogenic mechanism remains to be defined. To this end, our initial microarray analyses identified a LMP1-inducible gene, Ugene, originally characterized as a binding partner for uracil DNA glycosylase 2, which is highly expressed in malignant colon cancer. In this report, it was found that Ugene, designated herein as LMP1-induced protein (LMPIP), was induced, in a time-dependent manner, in EBV-infected peripheral blood mononuclear cells and LMP1-transfected 293 cells. Functionally, when compared with mock-transfected cells, overexpression of LMPIP in nasopharyngeal carcinoma (NPC) cell lines resulted in a decrease in reactive oxygen species production and maintained mitochondria membrane potential (Δψ) loss induced by H(2)O(2). The NPC cells transfected with LMPIP also showed a decrease in G1 population and an increase in the cell population in sub-G1 and multiploid phase, concomitant with increased levels of cell cycle activators, including cyclin D1 and CDK4. In contrast, silencing of LMPIP expression in the NPC tumor cell lines with short hairpin RNA interference revealed significantly decreased cell population at G1/S phase, while the number of cells in multiploid phase increased. Significantly, NPC cells with LMPIP knock-down also showed a decrease in tumorigenic and transforming activity induced by ectopic LMP1 expression, as determined by analyses of soft agar foci and tumor size in nude mice. Further, elevated LMPIP expression was also noted in cytoplasm and nuclei in EBV-infected NPC tumor cell mass and non-EBV-infected tumor cell lines. These results suggested that LMPIP may have an important mediator role in EBV-mediated neoplasm and may serve as a new target for therapy of tumors induced by EBV infection.

Mutation characteristics in type I collagen genes in Chinese patients with osteogenesis imperfecta.

Osteogenesis imperfecta is normally caused by an autosomal dominant mutation in the type I collagen genes COL1A1 and COL1A2. The severity of osteogenesis imperfecta varies, ranging from perinatal lethality to a very mild phenotype. Although there have been many reports of COL1A1 and COL1A2 mutations, few cases have been reported in Chinese people. We report on five unrelated families and three sporadic cases. The mutations were detected by PCR and direct sequencing. Four mutations in COL1A1 and one in COL1A2 were found, among which three mutations were previously unreported. The mutation rates of G>C at base 128 in intron 31 of the COL1A1 gene and G>A at base 162 in intron 30 of the COL1A2 gene were higher than normal. The patients' clinical characteristics with the same mutation were variable even in the same family. We conclude that mutations in COL1A1 and COL1A2 also have an important role in osteogenesis imperfecta in the Chinese population. As the Han Chinese people account for a quarter of the world's population, these new data contribute to the type I collagen mutation map.

Comparative proteomics analysis of human osteosarcomas and benign tumor of bone.

We conducted comparative proteomic analysis of osteosarcoma, with hopes of identifying the specific protein markers of osteosarcoma and improve the understanding of tumorigenesis and progression of osteosarcoma. Proteins extracted from osteosarcoma tissue and benign bone tumors, including osteoblastoma, chondroblastoma, and giant cell tumor of bone, were examined using two-dimensional gel electrophoresis followed by mass spectrometry analysis and database searches. We also validated the expression levels of interesting proteins by Western blotting assay and immunohistochemical staining. Intensity alterations of 30 spots were detected in osteosarcoma, and 18 of these spots were finally identified, including 12 up-regulated proteins and 6 down-regulated ones. The up-regulated proteins include VIM, TUBA1C, ZNF133, EZR, ACTG1, TF, and so on. The six down-regulated proteins include ADCY1, ATP5B, TUBB, RCN3, ACTB, and YWHAZ. Subsequent immunohistochemical staining and Western blotting assay for TUBA1C and ZNF133 in osteosarcoma samples confirmed the observation obtained by proteomic analysis. Our results suggest that these identified proteins may be potential biomarkers for osteosarcoma tumorigenesis and therapeutics. Aberrant expression of cytoskeletal- and microtubule-associated proteins in osteosarcoma may provide an advantage for tumor invasion and metastasis by affecting the stability of microtubule, which consequently influences the prognosis of patients.

Jejunojejunal intussusception secondary to metastasis from adenocarcinoma of the lung--a case report.

Small intestine metastasis from primary lung cancer is uncommon and jejunojejunal intussusception secondary to metastatic lung cancer is extremely rare. We report a case presenting with a one-week history of abdominal pain associated with poor appetite, vomiting and absent defaecation. Physical examination revealed abdominal distention with decreased bowel sounds. Chest roentgenogram showed a mass lesion in the right upper lung zone. Biopsy of the lung mass lesion confirmed adenocarcinoma of the lung. Computed tomography (CT) of the abdomen demonstrated a "target mass" lesion in the right lower abdomen, representing a small intestinal intussusception. Emergency segmental resection of the affected small intestine with jejunojejunal anastomosis was performed. Histological examination of the specimen revealed metastatic adenocarcinoma of lung origin. The patient had an uneventful postoperative course and was discharged home two weeks after surgery.

Implications of muon g -- 2 for supersymmetry and for discovering superpartners directly.

We study the implications of interpreting the recent muon g(mu) -- 2 deviation from the standard model prediction as evidence for virtual superpartners, with very general calculations that include effects of phases and are consistent with all relevant constraints. Assuming that the central value is confirmed with smaller errors, there are upper limits on masses: at 1.5 sigma, at least one superpartner mass is below about 450 GeV (550 GeV) for tan beta = 35 (50) and may be produced at the Fermilab Tevatron in the upcoming run.

Infrared patient positioning for stereotactic radiosurgery of extracranial tumors.

We report on a novel, non-invasive patient positioning system for radiosurgery of extracranial tumors. The system consisted of infrared cameras and reflective markers attached to the skin. Because localization accuracy is critical in radiosurgery, we performed a theoretical analysis of the accuracy of the system. A computer simulation program modeled errors in marker position, and was used to predict errors in targeting and study methods for minimizing errors. The use of redundant markers improved the overall accuracy of targeting. Experimental data was collected using a rigid torso phantom and correlated with theoretical results. The accuracy of the infrared system was compared with existing systems.

[Comparative study on efficacy of qinggan granule and bushen granule in treating chronic hepatitis C].

OBJECTIVE: To evaluate the efficacy of Qinggan Granule (QGG) and Bushen Granule (BSG) in treating chronic hepatitis C (CHC) from blood donors clinically, biochemically and pathologically as well as to explore the therapeutical principle and methods of TCM. METHODS: Sixty-six patients with CHC were divided into three groups, the 36 patients in the QGG group treated with QGG, the 18 patients in the BSG group treated with BSG and the 12 patients in the control group untreated. The dose of QGG and BSG given was 30 g each time, three times per day for 6 consecutive months. Clinical and serum biochemical parameters as well as pathological change of liver biopsy before and after treatment were observed dynamically and compared. RESULTS: After treatment, in the two treated group, clinical symptoms were improved significantly, alanine transaminase (ALT) and aspartate aminotransferase (AST) reduced markedly. Moreover, QGG showed the effects of increasing albumin and lowering alkaline phosphatase (ALP). On the contrary, ALT still remained as before but AST further increased in the control group. Pathological examination showed that the inflammatory grade (IG) decreased in 42.2% and fibrotic stage (FS) decreased 21.2% of the patients in the QGG group, but no significant changes of the two indexes occurred in the BSG group, while in the control group, IG unchanged and FS increased in 3 cases. Chevallier's semi-quantity system analysis showed significant decrease of both scores in the QGG group (P < 0.05), only decrease of IG in the BSG group, and slight raise of IG and significant increase of FS (P < 0.05) in the control group. CONCLUSION: Condition of chronic hepatitis C patient would deteriorate progressively if not treated in time, especially the development of fibrosis. QGG and BSG could improve the clinical symptoms significantly, lower ALT and AST, eliminate inflammatory damage in the liver, slow down or reverse liver fibrosis process with stable long-term effect. Though most of the patients present a Syndrome of Liver-Kidney Yin-deficiency, the effect of QGG is superior to that of BSG, suggesting that the treatment of CHC should mainly be clearing principle, and method of clearing Liver and eliminating Dampness may be more suitable for them.

SDS-induced conformational changes and inactivation of the bacterial chaperonin GroEL.

The inactivation and conformational changes of the bacterial chaperonin GroEL have been studied in SDS solutions with different concentrations. The results show that increasing the SDS concentration caused the intrinsic fluorescence emission intensity to increase and the emission peak to slightly blue-shift, indicating that increasing the SDS concentration can cause the hydrophobic surface to be slightly buried. The changes in the ANS-binding fluorescence with increasing SDS concentration also showed that the GroEL hydrophobic surface decreased. At low SDS concentrations, less than 0.3 mM, the GroEL ATPase activity increased with increasing SDS concentration. Increasing the SDS concentration beyond 0.3 mM caused the GroEL ATPase activity to quickly decrease. At high SDS concentrations, above 0.8 mM, the residual GroEL ATPase activity was less than 10% of the original activity, but the GroEL molecule maintained its native conformation (as indicated by the exposure of buried thiol groups, electrophoresis, and changes of CD spectra). The above results suggest that the conformational changes of the active site result in the inactivation of the ATPase even though the GroEL molecule does not markedly unfold at low SDS concentrations.

Unfolding and inactivation of Penaeus penicillatus acid phosphatase during denaturation by guanidine hydrochloride.

The conformational changes of penaeus penicillatus acid phosphatase during denaturation in guanidine hydrochloride solutions were studied by following changes in the intrinsic fluorescence, ultraviolet difference absorption, and circular dichroism spectra. Inactivation of the enzyme in guanidine hydrochloride solutions were compared with unfolding of the enzyme molecule. The results show that the extent of unfolding in guanidine solutions measured by several different methods closely coincide with each other and that slightly lower concentrations of guanidine are required to bring about inactivation than are required to produce significant conformational changes of the enzyme molecule. At the same concentrations, the inactivation rate constants are markedly faster than the rate constants for unfolding of the enzyme. The above results suggest that the active sites of this enzyme display more conformational flexibility than the enzyme molecule as a whole.

Nested PCR-SSCP assay for the detection of p53 mutations in paraffin wax embedded bone tumours: improvement of sensitivity and fidelity.

DNA extraction and PCR amplification from paraffin wax embedded bone tumour specimens present several difficulties, firstly, because of the abundant matrix they contain and, secondly, because decalcification often causes degradation of DNA. In this report, comparative studies were carried out to determine the most efficient method for DNA extraction and PCR amplification from such specimens. The results indicated that nested PCR produced appropriate strong reaction products with minimal background contamination. A method for DNA extraction from paraffin wax embedded bone tissue and a nested PCR-SSCP technique have been developed for use in such diagnostic specimens.