[ Ⅲ ]

Objective: To assess maxillary sagittal and vertical as well as upper airway changes immediately after mini-screw assisted rapid maxillary expansion (MARME) in class Ⅲ patients. Method: A consecutive sample of 48 class Ⅲ patients with maxillary transverse deficiency who visited the Department of Orthodontics, School & Hospital of Stomatology, Wuhan University between January 2013 and March 2023 was retrospectively collected. The sample was comprised of 24 growing patients (cervical vertebra maturation, CVM 1-4) and 24 nongrowing patients (CVM 5-6). Cone-beam CT scans before (T0) and immediately after MARME (T1) were imported into Dolphin Imaging software, and then voxel-based superimposition was conducted on the basis of the anterior cranial base. Sagittal and vertical changes of the maxillary landmarks (A, ANS, PNS, UI and Spr), as well as upper airway changes after MARME were measured on multiplanar reconstruction views. Wilcoxon signed-rank test was employed to analyze the changes after MARME. Mann-Whitney U test was employed to compare the changes between growing and non-growing patients. Results: Some class Ⅲ patients exhibited significant maxillary sagittal and vertical changes immediately after MARME. The amount of changes in midpalatal suture was 4.03 (2.99, 4.87) mm in growing patients, significantly larger than that in non-growing patients [2.27 (1.49, 3.64) mm] (U=3.18, P=0.001). In growing class Ⅲ patients, the forward changes of A, ANS, PNS, UI and Spr were 0.35 (0.06, 0.80), 0.48 (0.11, 0.88), 0.48 (0.13, 0.99), 0.53 (-0.33, 1.04) and 0.40 (0.03, 0.69) mm, respectively. Vertically, the downward changes of A, ANS, PNS, UI and Spr were 1.45 (0.99, 2.13), 1.18 (0.61, 1.95), 1.30 (0.91, 1.96), 1.20 (0.71, 1.83) and 1.30 (0.81, 1.73) mm, respectively. All changes were significantly different from 0 after treatment (P<0.05). In nongrowing patients, PNS moved forward by 0.18 (-0.08, 0.39) mm while other sagittal changes were statistically insignificant (P>0.05); vertically, the downward changes of A, ANS, PNS, UI and Spr were 0.90 (0.51, 1.39), 0.73 (0.41, 1.21), 0.70 (0.55, 1.08), 0.60 (0.36, 1.19) and 0.70 (0.55, 1.23) mm, respectively. Significant immediate increase of the nasopharynx volume and nasal width was obtained in both groups (P<0.05), and the changes of oropharynx volume and minimum cross-sectional area (MCA) presented as statistically insignificant (P>0.05). Conclusions: For growing class Ⅲ patients, besides transverse expansion, significant forward and downward changes of maxilla were obtained immediately after MARME. For non-growing patients, significant downward changes were observed, while sagittal changes were negligible. The nasopharynx volume increased in both growing and nongrowing class Ⅲ patients immediately after MARME, whereas, the changes of oropharynx volume and MCA presented as statistically insignificant.

Pulmonary nocardiosis with bloodstream infection diagnosed by metagenomic next-generation sequencing in a kidney transplant recipient: A case report

BACKGROUND

Pulmonary nocardiosis is difficult to diagnose by culture and other conventional testing, and is often associated with lethal disseminated infections. This difficulty poses a great challenge to the timeliness and accuracy of clinical detection, especially in susceptible immunosuppressed individuals. Metagenomic next-generation sequencing (mNGS) has transformed the conventional diagnosis pattern by providing a rapid and precise method to assess all microorganisms in a sample.

CASE SUMMARY

A 45-year-old male was hospitalized for cough, chest tightness and fatigue for 3 consecutive days. He had received a kidney transplant 42 d prior to admission. No pathogens were detected at admission. Chest computed tomography showed nodules, streak shadows and fiber lesions in both lung lobes as well as right pleural effusion. Pulmonary tuberculosis with pleural effusion was highly suspected based on the symptoms, imaging and residence in a high tuberculosis-burden area. However, anti-tuberculosis treatment was ineffective, showing no improvement in computed tomography imaging. Pleural effusion and blood samples were subsequently sent for mNGS. The results indicated Nocardia farcinica as the major pathogen. After switching to sulphamethoxazole combined with minocycline for anti-nocardiosis treatment, the patient gradually improved and was finally discharged.

CONCLUSION

A case of pulmonary nocardiosis with an accompanying bloodstream infection was diagnosed and promptly treated before the dissemination of the infection. This report emphasizes the value of mNGS in the diagnosis of nocardiosis. mNGS may be an effective method for facilitating early diagnosis and prompt treatment in infectious diseases, which overcomes the shortcomings of conventional testing.

[Analysis of the relationship between syncope and poor prognosis in patients with acute pulmonary embolism and related factors]

Objective: To explore the association between syncope and poor prognosis and related factors of syncope in patients with acute pulmonary embolism (APE). Methods: A total of 740 patients with first diagnosed APE treated in West China Hospital of Sichuan University from September 1, 2016 to December 30, 2019 were enrolled. The basic information and clinical information (including clinical manifestations, complications, auxiliary examination, treatment and prognosis, etc.) of the patients were obtained from inpatient medical records. The patients were divided into the syncope group and the non-syncope group according to whether they had syncope or not. The basic and clinical conditions of the two groups were compared, and the factors related to syncope in APE patients were analyzed by multiple logistic regression model. Results: The proportion of APE patients with syncope was 12.6% (93/740). Age was (59±16) years in the syncope group (93 cases) and (59±17) years in the non-syncope group (647 cases), with 57.0% (53/93) and 60.4% (391/647) males, respectively. The body mass index, in-hospital mortality, proportions with high risk APE and mechanical ventilation of the syncope group were higher than those of the non-syncope group [(24.5±4.0) kg/m² vs (23.3±3.8) kg/m², 16.1% vs 7.7%, 4.4% vs 1.3% and 9.7% vs 2.5%, respectively]. The length of hospital stay [M (Q₁, Q₃)] of the syncope group was longer than that of the non-syncope group [15 (10, 22) d vs 14 (9, 22) d], and the proportions with chest pain and hemoptysis were lower than those of the non-syncope group (19.4% vs 36.8% and 14.0% vs 27.2%, respectively) (all P values<0.05). Multivariate logistic regression analysis showed that enlargement of the right heart [OR (95%CI): 2.46 (1.07, 5.64)] was a factor associated with syncope in APE patients. Conclusion: The proportion of APE patients with syncope is relatively high and is associated with poor prognosis, while enlargement of the right heart is associated with syncope in APE patients.

[Comparison of risk factors and short-term and long-term prognosis of pulmonary embolism between the Tibetan and Han people]

Objective: To compare the differences of risk factors and prognosis of pulmonary embolism (PE) between the Tibetans and the Hans. Methods: Patients over 18 years old with confirmed PE and complete clinical data from West China Hospital of Sichuan University from January 2010 to January 2016 were prospectively enrolled and divided into Tibetan group and Han group. Clinical data were collected to compare risk factors and short-term prognosis between Han group and Tibetan group. In addition, a 2-year follow-up was conducted among patients after discharge to investigate the long-term prognosis. Results: A total of 90 patients in Tibetan group and 626 patients in Han group were finally included in this study. Patients in Tibetan group were younger than Han group [(52.2±15.8) vs (59.8±16.6) years old, P<0.001], and the proportion of elderly patients (age ≥70 years) in Tibetan group was significantly lower than that of Han group (15.6% vs 33.7%, P=0.001). The hemoglobin, hematocrit, platelet counts and fibrinogen in Tibetan group were higher than those in Han group [(134.0±32.0) vs (122.2±25.7) g/L, (41.2±9.2)% vs (37.6±7.3)% and (222.2±97.5)×10(9)/L vs (187.5±87.2)×10(9)/L, 3.71(2.51, 4.89) vs 3.31(2.44, 4.42) g/L; P<0.001, <0.001 and P=0.001, 0.048, respectively]. Malignancy and chronic obstructive pulmonary disease were more common in Han group (P=0.011, 0.001), while prior venous thromboembolism history, pregnancy or a history delivery within 1 month were more common in Tibetan group (P=0.041, 0.001). Both short-term and long-term mortality in Tibetan group were significantly lower than that in Han group (2.2% vs 11.5%, 13.6% vs 24.9%; P=0.005, 0.020). Conclusions: Hypercoagulable state plays an important role in the pathogenesis of PE in Tibetan patients. Both short-term and long-term prognosis of PE in Tibetan patients are better than that in Han patients.

[Experience of 14 cases using hemi-semilaminectomy microsurgery treating by spinal dural arteriovenous fistula]

Objective: To explore the efficacy and feasibility of the hemi-semilaminectomy microsurgical operation treatment of spinal dural arteriovenous fistula (SDAVF). Methods: The clinical data of 32 patients with SDAVF were analyzed retrospectively. Before operation all patients were diagnosed by spinal MRI and spinal angiography, 14 patients were treated by hemi-semilaminectomy approach and other 18 patients were by traditional laminectomy approach. All the data were analyzed by T test and P<0.05 was considered to have significant difference. Results: The nidus of SDAVF located on thoracic segments in 18 cases, lumbar segments in 12 cases, and cervical segment in 2 cases, which was fed by single artery. The hemi-semilaminectomy microsurgical operation showed shorter operation time, less bleeding, less hospitalization time and cost. All the patients followed-up for 6 months-2 years. Symptoms of all the patients were improved compared with those before surgery. Conclusions: On the premise of spinal angiography accurately positioning the location of fistula, the hemi-semi-laminectomy approach microsurgery clipping operation is safe and feasible, and the operation has fewer traumas, also helps to maintain the stability of spine.

[Risk factors of pulmonary embolism in senile and non-senile inpatients and the predictive value of Caprini risk assessment model in these two populations]

Objective: To investigate the risk factors of pulmonary embolism (PE) in senile and non-senile inpatients, and evaluate the predictive value of Caprini risk assessment model in these two populations. Methods: Case control study design was used in this study. All the PE patients diagnosed in West China Hospital of Sichuan University between January 2012 and December 2014 was included and divided into senile PE group (age ≥65 years old) and non-senile PE group (age <65 years old). Age matched controls (senile control group and non-senile control group) were selected from the patients admitted into the same departments during the same time period as PE patients, at a ratio of 2∶1. The risk factors of PE for senile and non-senile inpatients were investigated through comparing senile or non-senile PE patients with corresponding controls. All the subjects were retrospectively evaluated by Caprini risk assessment model, and the associations between risk stratifications and PE risk were analyzed. Results: A total of 135 senile PE patients and 212 non-senile PE patients were finally included in this study, with average age of (73.58±6.66) years old and (45.60±13.11) years old, respectively. And 233 age-matched senile controls and 418 non-senile controls were also included. The multivariate analysis showed diabetes (OR=4.08, 95%CI: 1.58-10.51, P=0.004) , heart failure (OR=3.67, 95%CI: 1.10-12.20, P=0.034) , swollen legs (OR=10.50, 95%CI: 5.57-19.79, P<0.001) , severe lung disease (OR=2.05, 95%CI: 1.08-3.90, P=0.028) , patient confined to bed (>72 h) (OR=58.33, 95%CI: 7.46-456.17, P<0.001) were independent risk factors of PE in senile patients, while obesity[body mass index (BMI)≥25 kg/m(2)](OR=2.72, 95%CI: 1.42-5.24, P=0.003), history of deep venous thrombosis (DVT)/PE (OR=17.54, 95%CI: 2.74-112.19, P=0.002) , hip, pelvis, or leg fracture (OR=18.31, 95%CI: 1.97-170.11, P=0.011) , swollen legs (OR=18.53, 95%CI: 11.29-30.40, P<0.001) , severe lung disease ( OR=4.11, 95%CI: 2.41-7.00, P<0.001) , patient confined to bed (>72 h) (OR=4.04, 95%CI: 2.03-8.04, P<0.001) were independent risk factors of PE in non-senile patients. Among the senile patients, the risk of PE increased with the increase of Caprini risk levels; compared with Caprini moderate risk, classifications of high risk and highest risk were associated with 4.64-fold (95%CI: 1.05-20.44, P=0.043) and 10.74-fold (95%CI: 2.46-46.94, P=0.002) increased risk of PE, respectively; within the highest subgroup, the per 2-score increase of Caprini score was associated with 3.02-fold (95%CI: 1.76-5.19, P<0.001) increased risk of PE. Among those non-senile patients, the risk of PE for Caprini low risk and high risk patients was not significantly different, compared with Caprini moderate risk patients; however, the highest risk was still associated with 3.94-fold (95%CI: 2.39-6.51, P<0.001) increased risk of PE compared with moderate risk; within this subgroup, the per 2-score increase of Caprini score was associated with 2.13-fold (95%CI: 1.21-3.73, P=0.008) increased risk of PE. Conclusions: Swollen legs, severe lung disease, confined to bed (>72 h) are common PE risk factors among both senile and non-senile inpatients. Diabetes, heart failure are unique PE risk factors for senile inpatients, while obesity (BMI≥25 kg/m(2)), history of DVT/PE, hip, pelvis, or leg fracture are unique PE risk factors for non-senile inpatients. The Caprini risk assessment model has better predictive value in senile patients than non-senile patients, while Caprini highest risk classification is companied by significantly increased risk of PE in both populations.

Expression of inflammatory cytokines in ovarian epithelial cancer and their correlation

This study investigates the expression of interleukin (IL)-17 (IL-17A and IL-17D) and its role in ovarian epithelial tumor and its correlation with the clinical characteristics. Fifty malignant ovarian epithelial tumor specimens were collected after surgery and set as group A. Ten benign epithelioma specimens and ten normal epithelial specimens were set as group B and C, respectively. The expression of IL-17A and IL-17D in the three groups was detected using the EnVision method, and the correlation of positive expression rate with pathological type, clinical stage, presence of ascites and differentiation degree was analyzed. Group A had higher expression of IL-17A and IL-17D compared to group B and C (p less than 0.05). The expression rate was in correlation to clinical stage and differentiation degree, but in no correlation to pathological type and presence of ascites. The expression rate of malignant epithelioma in the early stage was lower than that in the late stage (p less than 0.05). Lower differentiation degree indicated higher expression rate (p less than 0.05). Pathological type and presence of ascites had no remarkable influence on the expression rate (p>0.05). Study of the expression of IL-17 provides theoretical support for the clinical treatment and prognosis prediction of ovarian epithelial tumor.

[Risk factors of venous thromboembolism recurrence and the predictive value of simplified pulmonary embolism severity index in medical inpatients]

OBJECTIVE

To explore the risk factors of venous thromboembolism (VTE) recurrence and the predictive value of simplified pulmonary embolism severity index (sPESI) in medical inpatients.

METHODS

A total of 149 consecutive patients with first diagnosed VTE from the medical departments of West China Hospital of Sichuan University from January 2011 and December 2012 were enrolled and followed-up for 24 months. The VTE recurrence rate was calculated and univariate and multivariate cox proportional hazards regression analysis were performed to identify the risk factors associated with VTE recurrence. All the patients were evaluated by sPESI, and survival analysis was used to explore its value in predicting VTE recurrence in these medical patients.

RESULTS

Out of the included 149 patients, 23(15.4%) patients had VTE recurrence during the 2 years' follow-up and median recurrence time was 167 days. The univariate analysis showed bed rest, severe lung disease, nephrotic syndrome, inappropriate anticoagulant therapy, smoking, diabetes, and malignant neoplasm might be associated with VTE recurrence (P=0.043, 0.006, 0.009, 0.032, 0.098, 0.048, 0.021). Among these risk factors, the multivariate analysis revealed severe lung disease, nephrotic syndrome, and malignant neoplasm were the independent risk factors (HR=3.45, 5.67, 3.60; P=0.020, 0.020, 0.047); while for inappropriate anticoagulant therapy, the P value was marginal (HR=3.94, 95% CI: 0.99-15.63, P=0.051). The median sPESI scores of the patients with VTE recurrence was higher than that of the patients without VTE recurrence[1(1, 2) vs 0(0, 1), P=0.001], and patients with sPESI≥1 were associated with 5.57-fold increased risk of VTE recurrence compared with patients with sPESI=0 (95%CI: 1.79-17.30, P=0.001). Survival analysis also showed that the 2-year cumulative VTE recurrence rate of patients with sPESI≥1 was significant higher than that of patients with sPESI=0 (38.4% vs 5.7%, P=0.001).

CONCLUSIONS

The medical VTE patients have high VTE recurrence risk, and severe lung disease, nephrotic syndrome, malignant neoplasm and inappropriate anticoagulant therapy are important risk factors of VTE recurrence. The sPESI has predictive value for VTE recurrence in medical patients.

[Outcome of childhood T-cell acute lymphoblastic leukemia: a report of 99 cases]

OBJECTIVE

To explore the incidence, clinical characteristics and prognosis of childhood T-cell acute lymphoblastic leukemia (T-ALL) enrolled in protocol ALL-2005.

METHOD

Retrospective reviews of patients diagnosed as having T-ALL were studied in the period between May 2005 and August 2013 in Shanghai Children's Medical Center. Predictive values of early treatment responses, including prednisone response, bone marrow morphology on day 35 during induction chemotherapy, and minimal residual disease (MRD) monitored by flow cytometry on day 35 and 55, were analyzed. The Kaplan-Meier method was used to assess the survival rates.

RESULT

Ninety-nine evaluable patients aged 1-18 years with newly diagnosed T-ALL were enrolled in protocol ALL-2005. The median follow-up period for patients remaining alive in continuous remission was 60 months (24-109 months). The 5-year event free survival (EFS) and overall survival (OS) rates for these patients were 65% and 69%, respectively. Forty-three (43%) patients were older than 10 years at diagnosis. A total of 61 patients presented with initial white blood cell count (WBC)≥50×10(9)/L. Thirty-seven patients with mediastinal mass were found in this study. Seventy-one patients were defined as prednisone good responders (PGR) on day 8 of prednisone therapy. Ninty-four patients achieved complete remission (CR) on day 35 of induction therapy. MRD negative status (<0.01%) on day 35 were seen in 55% of the 42 assessed patients. MRD negative status on day 55 was seen in 78% of the 52 assessed patients. Patients with high MRD (>1%) on day 55 5-year EFS was 40% were associated with poor prognosis (P=0.03). Early T-cell precursor (ETP) subtype was not associated with treatment outcome in this study. Six patients abandoned therapy, 10 lost to follow-up, 22 had relapsed disease, 1 was diagnosed as having a second tumor and 20 patients died.

CONCLUSION

Overall outcome for T-ALL on protocol ALL-2005 is favorable. MRD results on day 55 of induction therapy have important prognostic and therapeutic implications.

ERCC2 rs13181 polymorphism association with glioma susceptibility in a Chinese population

We conducted a case-control study to investigate the role of ERCC2 rs13181 polymorphism in glioma development. A total of 165 patients who were histopathologically diagnosed to have gliomas and 330 controls were collected at Jiujiang First People's Hospital between July 2012 and June 2014. The ERCC2 rs13181 polymorphism was analyzed using a polymerase chain reaction -restriction fragment length polymorphism assay. By conditional regression analysis, we found that the GG genotype of the ERCC2 rs13181 polymorphism is associated with susceptibility to gliomas when compared to the TT genotype (OR = 2.05, 95%CI = 1.11-3.79). In the recessive model, the GG genotype is associated with an increased risk of gliomas when compared with the TT+TG genotype (OR = 1.87, 95%CI = 1.03-3.37). In conclusion, the ERCC2 rs13181 polymorphism is correlated with an increased risk of gliomas in codominant and recessive models, which suggests that this polymorphism could influence the etiology of gliomas.

Influence of Rho kinase inhibitor fasudil on late endothelial progenitor cells in peripheral blood of COPD patients with pulmonary artery hypertension

OBJECTIVE

To investigate the influence of Fasudil, a Rho inhibitor on the number and functions of the late endothelial progenitor cells in peripheral blood of chronic obstructive pulmonary diseases (COPD) patients with pulmonary artery hypertension.

BACKGROUND

It is not clear yet, whether Rho Kinase Inhibitor Fasudil can reduced pulmonary artery pressure through improving lung endothelial function.

METHODS

80 COPD patients with pulmonary artery hypertension were selected and divided into two groups: the treatment group and the control group, which had 40 patients, respectively. Changes in the number and function of the late endothelial progenitor cells in peripheral blood of the patients before and after the treatment were compared between the two groups. The changes on the pulmonary artery pressure were also compared.

RESULTS

The number of the late endothelial progenitor cells in peripheral blood of the treatment group increased and the function was enhanced. The pulmonary artery pressure was reduced. The difference before and after the treatment and with the control group was statistically significant (p < 0.05).

CONCLUSIONS

The Rho-kinase inhibitor Fasudil increased the number and enhanced the function of the late endothelial progenitor cells in peripheral blood of COPD patients with pulmonary artery hypertension (Tab. 3, Fig. 2, Ref. 17).

Inhibitor of signal transducer and activator of transcription 3 (STAT3) suppresses ovarian cancer growth, migration and invasion and enhances the effect of cisplatin in vitro

The aim of the present study was to investigate the anti-ovarian cancer effect of the inhibitor of signal transducer and activator of transcription 3 (STAT3), WP1066. Western blot was used to detect the phosphorylation of STAT3 in ovarian cancer cell line SKOV3 and cisplatin-resistant ovarian cancer cell line SKOV3/DDP. MTT and colony-forming assays were performed to evaluate the viability and growth of ovarian cancer cells. The apoptosis of ovarian cancer cells was determined by flow cytometry. The wound healing assay and Transwell assay were performed to examine the migration and invasion of ovarian cancer cells. WP1066 significantly inhibited the phosphorylation of STAT3 in SKOV3 and SKOV3/DDP cells. WP1066 treatment inhibited the proliferation and clonogenicity of both SKOV3 and SKOV3/DDP cells. After WP1066 treatment for 24 h, the apoptosis rates of SKOV3 and SKOV3/DDP cells were significantly increased compared with the control cells. After treatment with WP1066, the reduction of the wound gaps was significantly less in both SKOV3 and SKOV3/DDP cells. WP1066 also significantly inhibited the invasion capacity of SKOV3 and SKOV3/DDP cells compared with the control group. Treatment with WP1066 combined with cisplatin significantly increased proliferation inhibition and apoptosis in SKOV3 and SKOV3/ DDP cells compared with treatment with cisplatin alone. A synergistic action between WP1066 and cisplatin on the proliferation and apoptosis of ovarian cancer cells was determined. In conclusion, inhibition of STAT3 may suppress the proliferation, migration and invasion, induce apoptosis and enhance the chemosensitivity of ovarian cancer cells, indicating that STAT3 is a new therapeutic target of ovarian cancer.

Fragmentation mechanisms for methane induced by 55 eV, 75 eV, and 100 eV electron impact

The fragmentation of CH4 (2+) dications following 55 eV, 75 eV, and 100 eV electron impact double ionization of methane was studied using a cold target recoil-ion momentum spectroscopy. From the measured momentum of each recoil ion, the momentum of the neutral particles has been deduced and the kinetic energy release distribution for the different fragmentation channels has been obtained. The doubly charged molecular ions break up into three or more fragments in one or two-step processes, resulting in different signatures in the data. We observed the fragmentation of CH4 (2+) dications through different mechanisms according to the momentum of the neutral particles. For example, our result shows that there are three reaction channels to form CH2 (+), H(+), and H, one synchronous concerted reaction channel and two two-step reaction channels. For even more complicated fragmentation processes of CH4 (2+) dications, the fragmentation mechanism can still be identified in the present measurements. The slopes of the peak in the ion-ion coincidence spectra were also estimated here, as they are also related to the fragmentation mechanism.

A novel evaluation index for adolescent idiopathic scoliosis progression measurement and diagnosis

Adolescent idiopathic scoliosis is a trunk deformity of the spine with lateral deviation and rotation in the transverse plane. The most traditional measurement index and parameter for scoliosis diagnosis is the Cobb's angle, which evaluates the curves of the scoliotic spine on the radiographic projection of the trunk. Although this method is widely accepted as the benchmark in scoliosis assessment, it has some limitations and restrictions in practical applications because it is measured on a PA (posterior-anterior or back to front) X-ray image, such as potential harmfulness from radiation exposure and high cost.In this paper, a novel evaluation index for adolescent idiopathic scoliosis measurement and diagnosis is introduced to complement the existing assessment index, such as the Cobb's angle, the differences of shoulder height, etc. The new evaluation index is based on the phenomenon of the tilt and deviation of the vertebras in a scoliotic spine, which forms the tilt angles between each pair of adjacent vertebras.A data sample of 30 X-ray images of scoliotic spines was used in this research to evaluate and examine the usability and validity of the new index. The Cobb's angle and the new index were calculated and compared using the same data sample. The correlation between the Cobb's angle and the index was also determined, and a high correlation is found which demonstrated the usefulness of this proposed index. In this paper, it has been shown that the newly-proposed index has the potential to be used as a tool to support the traditional scoliosis measurement methods.This method can also be generalized on the sagittal plane to define other evaluation indices for assessing the severity of kyphosis and lordosis. The idea of using angular separation to evaluate spinal deformity in multiple planes or in three-dimensional spaces will be discussed in future research.

KiSS1 inhibits growth and invasion of osteosarcoma cells through inhibition of the MAPK pathway

As a metastasis suppressor, KiSS1 has been implicated in numerous human cancers. However, recent studies have demonstrated that KiSS1 promotes tumor growth and metastasis in breast cancer, and it is unclear about the expression and function of KiSS1 in human osteosarcoma (OS). The aim of the present study was to investigate the role and molecular mechanisms of KiSS1 in human OS. The expression of KiSS1 was assessed by immunohistochemical assay using a tissue microarray procedure in forty cases of OS tissues. A gain-of-function approach was used to observe the effects of lentiviral vector-mediated overexpression of KiSS1 (Lv-KiSS1) on the biological behaviors including proliferative activities and invasive potential of OS MG-63 cells, indicated by MTT and Transwell assays, respectively. The results showed that the expression of KiSS1 protein in OS tissues was significantly lowered compared to that in adjacent non-cancerous tissues (ANCT) (42.5% vs 70.0%, P=0.023), and had negative correlation with distant metastases of the tumor (P=0.019). Overexpression of KiSS1 inhibited proliferation and invasion of OS cells with the decreased expression of p38 MAPK and matrix metalloproteinase-9 (MMP-9). Taken together, our findings indicate that the decreased expression of KiSS1 is correlated with distant metastasis of OS, and KiSS1 may function as a tumor suppressor in OS cells through inhibition of the MAPK pathway, suggesting that KiSS1 may serve as a potential therapeutic target for the treatment of cancer.

A new absolute extreme ultraviolet image system designed for studying the radiated power of the Joint Texas Experimental Tokamak discharges

A bolometer imaging system mounted on different toroidal and poloidal locations used for radiation observation has been developed in the Joint Texas Experimental Tokamak (J-TEXT tokamak). Three miniature pinhole AXUV16ELG (16 elements absolute extreme ultraviolet silicon photodiodes) array cameras, which are settled down in the same toroidal position but in three different poloidal places, can provide a broad viewing angle that covers the whole plasma cross-section, and hence can measure the total radiated power and provide the radiated emissive profile, while nine AXUV10EL (10 elements absolute extreme ultraviolet silicon photodiodes) array cameras are divided into three groups and will be mounted on different toroidal locations to observe the toroidal radiated power distribution. Among these detectors, one element of the AXUV16ELG array is absolutely calibrated by the synchrotron radiation source to verify the system reliability. Although there are some discrepancies between the typical responsivity given by IRD Co. and the calibrated results, it is confirmed that the discrepancies have no major effect on the final result after the simulation. The details of the system as well as observations are presented in the paper.

Demonstration of bulk acceleration of ions in ultraintense laser interactions with low-density foams

Ion acceleration inside low-density foams irradiated by ultraintense laser pulses has been studied experimentally and theoretically. It is found that the ion generation is closely correlated with the suppressed hot electron transport inside the foams. Particle-in-cell simulations suggest that localized electrostatic fields with multi peaks around the surfaces of lamellar layers inside the foams are induced. These fields inhibit hot electron transport and meanwhile accelerate ions inside the foams, forming a bulk acceleration in contrast to the surface acceleration at the front and rear sides of a thin solid target.

Structural genomics efforts at the Chinese Academy of Sciences and Peking University

Structural genomics efforts at the Chinese Academy of Sciences and Peking University are reported in this article. The major targets for the structural genomics project are targeted proteins expressed in human hematopoietic stem/progenitor cells, proteins related to blood diseases and other human proteins. Up to now 328 target genes have been constructed in expression vectors. Among them, more than 50% genes have been expressed in Escherichia coli, approximately 25% of the resulting proteins are soluble, and 35 proteins have been purified. Crystallization, data collection and structure determination are continuing. Experiences accumulated during this initial stage are useful for designing and applying high-throughput approaches in structural genomics.

[The development and application of oxypathor of standard atmosphere]

This paper introduces a newly-developed oxypathor under one absolute atmosphere. It provides both oxygen and mixed-oxygen therapies, featuring oxygen-supply and oxygen-inhalation of hyperbaric oxygen chamber, and broaden the clinical applications of oxygen-therapy, which gave shown satisfactory results.

Electroporation of DNA sequences from the pathogenicity locus (PaLoc) of toxigenic Clostridium difficile into a non-toxigenic strain

Toxigenic Clostridium difficile is the etiologic agent of C. difficile-associated diarrhoea (CDAD), the most common cause of hospital-acquired infectious diarrhoea. The genes tcdA and tcdB, which encode for the toxin A and B proteins, are part of the pathogenicity locus (PaLoc) of toxigenic C. difficile. Genetic and virulence studies at the molecular level in C. difficile have been hindered by the lack of techniques for DNA manipulation in this species. We describe the electroporation of DNA fragments from a toxigenic isolate into a non-toxigenic strain of C. difficile. Using previously described methods of electroporation into Clostridium spp., the complete toxin B gene and polymerase chain reaction (PCR) fragments of the PaLoc were cloned and electroporated into a non-toxigenic strain of C. difficile. The resulting transformed clones were screened for the introduced gene fragments by PCR, which confirmed their presence. This is the first description of introduction of DNA into C. difficile by electroporation.

Phosphorus export by runoff from agricultural field plots with different crop cover in Lake Taihu watershed

Runoff and soil losses from agricultural fields are investigated as major nonpoint sources of phosphorus (P) entering lakes of Eastern China. There is relatively little information on P transport from ricefield and cropland of Lake Taihu watershed in Eastern China. Soil and P in surface runoff from a series of plots in the watershed were evaluated under simulated rainfall conditions. The objectives of this study were to evaluate the effects of crop cover, slope, and fertilizer application on P concentrations in surface runoff and eroded soil. Accumulated sediment yields varied from 7.1 to 300 g/m2 for croplands, depending on management practices. For all experiment plots, weighted average concentrations of total-P (TP), dissolved P (DP) and particulate P (PP) are much higher than 0.02 mg/L, the limiting concentration for lake water. This result showed the potential contamination of lake water from agricultural surface runoff. Accumulated TP losses were 3.8 and 18.8 mg/m2 for ricefield and cropland, respectively. The estimated annual loss of TP was 0.74 kg/(hm2.a) for cropland. Most of P loss is in the PP form, which accounts for more than 90% of TP loss for cropland.

Synthesis, characterization and photodynamic activity of amino-substituted hypocrellin derivatives

Three new hypocrellin derivatives, amino- or amino acid-substituted on the side ring of hypocrellin B (HB), were synthesized by the reactions of HB with 3-methoxypropylamine, 6-aminohexanoic acid and gamma-amino-n-butyric acid, respectively. The structures of these compounds were characterized with proton nuclear magnetic resonance spectra, infrared spectra and mass spectra. The UV-visible absorption spectra, singlet oxygen-generating quantum yield and amphiphilicities of hypocrellin derivatives were measured and compared with HB, the parent compound. These derivatives showed strong absorption in the domain of the phototherapeutic window (600-900 nm) and improved amphiphilicity. HB and the derivatives were preliminarily tested for their photodynamic effects on human oral cavity epithelial carcinoma KB cell line in vitro. Two amino acid-substituted hypocrellins showed phototoxicity to the KB cell line. At an inhibitory dosage of 50% killing only 0.51 mumol L-1 compound 3 (or 0.88 mumol L-1 compound 2) and 0.5 J cm-2 irradiation were required. The hypocrellins exhibited some dark toxicity to the KB cell line. HB and amino acid-substituted hypocrellins showed lower dark toxicity to the KB cell line than amino-substituted hypocrellins in the assessment of cell survival.

Resistance to moxifloxacin in toxigenic Clostridium difficile isolates is associated with mutations in gyrA

Clostridium difficile is the etiological agent of antibiotic-associated colitis and the most common cause of hospital-acquired infectious diarrhea. Fluoroquinolones such as ciprofloxacin are associated with lower risks of C. difficile-associated diarrhea. In this study, we have analyzed 72 C. difficile isolates obtained from patients with different clinical courses of disease, such as toxic megacolon and relapses; the hospital environment; public places; and horses. They were investigated for their susceptibilities to moxifloxacin (MXF), metronidazole (MEO), and vancomycin (VAN). Mutants highly resistant to fluoroquinolones were selected in vitro by stepwise exposure to increasing concentrations of MXF. The resulting mutants were analyzed for the presence of mutations in the quinolone resistance-determining regions of DNA gyrase (gyrA), the production of toxins A and B, and the epidemiological relationship of these isolates. These factors were also investigated using PCR-based methods. All strains tested were susceptible to MEO and VAN. Twenty-six percent of the clinical isolates (19 of 72) were highly resistant to MXF (MIC > or = 16 microg/ml). Fourteen of these 19 strains contained nucleotide changes resulting in amino acid substitutions at position 83 in the gyrA protein. Resistant strains selected in vitro did not contain mutations at that position. These findings indicate that resistance to MXF in a majority of cases may be due to amino acid substitution in the gyrA gene.

Isolation of Clostridium innocuum from cases of recurrent diarrhea in patients with prior Clostridium difficile associated diarrhea

Clostridium innocuum isolates resistant to vancomycin (MIC values of 16-24 microg/mL) were isolated from three patients with recurrent Clostridium difficile -associated diarrhea (CDAD). We discuss the clinical significance and problems associated with the identification and differentiation of these two clostridial species, which may result in misdiagnosis of patients.

[Effects of millimeter wave combined with gamma-ray radiation on human tongue squamous cell carcinoma cell]

OBJECTIVE

To observe the effects of millimeter wave combined with (60)Co gamma-ray radiation on human tongue squamous cell carcinoma cell(Tca8113).

METHODS

Using mm-wave combined with (60)Co gamma-ray to irradiate Tca8113 cell suspensions. The colony forming inhibition efficiency was observed three weeks later. 24 hours after radiation, the samples were observed under electron microscope.

RESULTS

The study showed that the radiation could result in significant decrease of the colony forming efficiency (P<0.001). The inhibition efficiency was higher when the samples were exposed to high power density mm-wave or for a long duration (P<0.05 or P<0.01). The inhibiting effect in combined groups was more obvious than in singly radiated group (P<0.001 or P<0.05). There was no difference between 'R+HL' group and 'HL+R' group (P>0.05). Electron microscopy showed the cells' suprastructures had some injuries and regressive changes. And more serious changes existed in 'H' group.

CONCLUSION

It could be concluded that mm-wave radiation could efficiently inhibit the colony forming capability of Tca8113 cell. And mm-wave radiation could lead to morphological changes of exterior or interior ultrastructures of Tca8113 cell.

Molecular typing methods for the epidemiological identification of Clostridium difficile strains

Toxigenic Clostridium difficile is the etiologic agent of C. difficile-associated diarrhea (CDAD), the most common cause of nosocomial diarrhea. Cross-infection between patients and transmission through the environment and medical personnel are important factors in the acquisition of CDAD. In order to understand differences in epidemiology and pathogenesis, a number of typing schemes have been developed. We will review the typing methods used to study the epidemiology of C. difficile infections and how they have evolved from a phenotypic identification to state of the art molecular methods, detecting genetic polymorphisms among strains. These molecular methods include PCR-based methods (arbitrarily primed-PCR [AP-PCR] and PCR ribotyping), restriction endonuclease analysis (REA) and pulse field gel electrophoresis (PFGE). The application, usefulness and feasibility of these methods are compared and discussed. Finally, the role of genomics as a tool to investigate CDAD is introduced.

Anaerobic bacteria and intrahepatic stones: detections of Clostridium sp. and Bacteroides fragilis

OBJECTIVE

To detect anaerobic bacteria Clostridium sp. and Bacteroides fragilis in intrahepatic stones by molecular genetic method.

METHODS

DNA was extracted from 59 stone samples and subjected to polymerase chain reaction (PCR) amplification targeting the 16S rRNA gene of Clostridium sp. and the glutamine synthetase gene of Bacteroides fragilis. Single-strand conformational polymorphism (SSCP) analysis was performed to identify the Clostridium sp.

RESULTS

16S rRNA gene sequences for Clostridium sp. were identified in 49 stones (83%, 49/59). The two most common groups were detected in 19 (41%) and 17 (37%) of the 46 samples using SSPC analysis, and 25/59 (42%) stones were tested positive for Bacteroides fragilis.

CONCLUSIONS

Anaerobes such as Clostridium sp. and Bacteroides fragilis present in intrahepatic stones and may play a role in stone formation. PCR is a useful technique to detect fastidious pathogens, which are difficult to culture. SSCP of PCR products is a rapid method in differentiating bacterial species.

Genotyping of Bacteroides fragilis isolates from stool specimens by arbitrarily-primed-PCR

In order to determine genetic relatedness of Bacteroides fragilis isolates from different clinical sources, arbitrarily primed polymerase chain reaction (PCR) (AP-PCR) was used to compare 17 strains isolated from patients with inflammatory bowel disease (IBD) and 20 strains isolated from foals with diarrhea. Three reference ATCC strains were also analyzed. Eighteen unique types were identified with a 22-mer arbitrary primer (ERIC-2) among the 20 patient isolates. Types 1 (enterotoxigenic) and 9 (nonenterotoxigenic), were each found in the stools of two patients. All other isolates showed a distinct and unique DNA banding pattern indicating a high degree of genotypic variability. Eleven types were identified among the foal isolates. Type 20, a nonenterotoxigenic type, was present in 30% of the foals. No correlation was found between the human and horse isolates. No clear relationship between a disease state (diarrhea or IBD) and specific types was observed. AP-PCR will be useful as a rapid method to determine genetic relatedness and in future epidemiologic studies of diarrheal diseases due to B. fragilis.

Persistence of an endemic (toxigenic) isolate of Clostridium difficile in the environment of a general medicine ward

The epidemiology of Clostridium difficile-associated diarrhea (CDAD) in an endemic setting was investigated by use of DNA typing methods to determine the strain identity of C. difficile isolates. Two predominant toxigenic clones were found in the environment and accounted for 29.8% (type 1) and 15.5% (type 2) of CDAD cases, respectively. In endemic settings, the environment and cross-transmission may play a role in acquisition of CDAD.

Occurrence of Bacteroides fragilis enterotoxin gene-carrying strains in Germany and the United States

Ninety-three Bacteroides fragilis isolates from different geographic locations were analyzed for the presence of an enterotoxin-encoding gene. It was shown that blood culture isolates were more likely to carry this gene than strains from other sources. All enterotoxin-positive strains belonged to the PCR fingerprint group I.

Isolation and molecular characterization of Clostridium difficile strains from patients and the hospital environment in Belarus

Toxigenic Clostridium difficile is the most common etiologic agent of hospital-acquired diarrhea in developed countries. The role of this pathogen in nosocomial diarrhea in Eastern Europe has not been clearly established. The goal of this study was to determine the prevalence of C. difficile in patients and the hospital environment in Belarus and to characterize these isolates as to the presence of toxin genes and their molecular type. C. difficile was isolated from 9 of 509 (1.8%) patients analyzed and recovered from 28 of 1,300 (2. 1%) environmental sites cultured. A multiplex PCR assay was used to analyze the pathogenicity locus (PaLoc) of all isolates, and strain identity was determined by an arbitrarily primed PCR (AP-PCR). The targeted sequences for all the genes in the PaLoc were amplified in all C. difficile strains examined. A predominantly homogeneous group of strains was found among these isolates, with five major AP-PCR groups being identified. Eighty-three percent of environmental isolates were classified into two groups, while patient isolates grouped into three AP-PCR types, two of which were also found in the hospital environment. Although no data on the role of C. difficile infection or epidemiology of C. difficile-associated diarrhea (CDAD) in this country exist, the isolation of toxigenic C. difficile from the hospital environment suggests that this pathogen may be responsible for cases of diarrhea of undiagnosed origin and validates our effort to further investigate the significance of CDAD in Eastern Europe.

Analysis of the pathogenicity locus in Clostridium difficile strains

The genes for Clostridium difficile toxins A and B (tcdA and tcdB) are part of a 19.6-kb pathogenicity locus (PaLoc) that includes the genes tcdD, tcdE, and tcdC. To determine whether the C. difficile PaLoc is a stable and conserved genetic unit in toxigenic strains, a multiplex polymerase chain reaction was used to analyze 50 toxigenic, 39 nontoxigenic, and 2 toxin-defective isolates. The respective amplicons were identified for tcdA-E in the toxigenic isolates; these were absent in the nontoxigenic isolates. C. difficile P-829 lacked at least a fragment of tcdD, tcdB, tcdE, and tcdC, but tcdA was present. C. difficile 8864 had deletions in the tcdA and tcdC genes. These data suggest that the PaLoc is highly stable in toxigenic C. difficile, nontoxigenic isolates lack the unit, and isolates with a defective PaLoc can still cause clinical disease. Further studies are needed to define the role of individual genes in the pathogenesis of C. difficile-associated diarrhea.

Bacteroides fragilis enterotoxin gene sequences in patients with inflammatory bowel disease

We identified enterotoxigenic Bacteroides fragilis in stool specimens of patients with inflammatory bowel disease and other gastrointestinal disorders. The organism was detected in 11 (13.2%) of 83 patients with inflammatory bowel disease. Of 57 patients with active disease, 19.3% were toxin positive; none of those with inactive disease had specimens positive for enterotoxigenic Bacteroides fragilis gene sequences.

Clostridium difficile: a survey of fecal carriage in cats in a veterinary medical teaching hospital

Fecal samples collected from 245 cats over a 6-month period were analyzed for the presence of Clostridium difficile. After culture on selective media, isolates were identified by a latex agglutination test, and the presence of toxin A and toxin B gene sequences was determined by polymerase chain reaction. Clostridium difficile was isolated from 23 (9.4%) of the cats, and 34.8% of that group were colonized with toxigenic strains. All of the cats colonized with toxigenic C. difficile had > or = 1 of the risk factors (antibiotic use, antineoplastic therapy, immunosuppressive virus infection) associated with C. difficile infection in humans. Clostridium difficile was not found in any of the cats from a clinically healthy outpatient group of cats examined from the same hospital nor in cats from a specific-pathogen-free research colony on the same campus tested during the same time period. The data obtained in this study confirm the presence of C. difficile in cats at a veterinary teaching hospital. DNA fingerprinting analysis of these isolates allowed separation of the strains into 5 groups. Type 4 strain found in 7 cats was also recovered from the floor drain in the same hospital, suggesting a possible source of infection. Whether the organism is of clinical significance in diarrheal diseases of cats remains to be determined.

Detection of Bacteroides fragilis enterotoxin gene by PCR

Bacteroides fragilis constitutes about 1% of the bacterial flora in intestines of normal humans. Enterotoxigenic strains of B. fragilis have been associated with diarrheal diseases in humans and animals. The enterotoxin produced by these isolates induces fluid changes in ligated intestinal loops and an in vitro cytotoxic response in HT-29 cells. We developed a nested PCR to detect the enterotoxin gene of B. fragilis in stool specimens. After DNA extraction, a 367-bp fragment was amplified with two outer primers. The amplicon from this reaction was subjected to a second round of amplification with a set of internal primers. With these inner primers, a 290-bp DNA fragment was obtained which was confirmed as part of the B. fragilis enterotoxin gene by Southern blotting with a nonradioactive internal probe and a chemiluminescence system. By this approach, B. fragilis enterotoxin gene sequences were detected in eight known enterotoxigenic human isolates and nine enterotoxigenic horse isolates. No amplification products were obtained from DNA extracted from 28 nonenterotoxigenic B. fragilis isolates or B. distasonis, B. thetaiotaomicron, B. uniformis, B. ovatus, Escherichia coli, or Clostridium difficile. The sensitivity of this assay allowed us to detect as little as 1 pg of enterotoxin DNA sequences or 100 to 1,000 cells of enterotoxigenic B. fragilis/g of stool. Enterotoxin production of all isolates was confirmed in vitro in HT-29 cells. A 100% correlation was obtained between enterotoxin detection by cytotoxin assay and the nested PCR assay. This rapid and sensitive assay can be used to identify enterotoxigenic B. fragilis and may be used clinically to determine the role of B. fragilis in diarrheal diseases.

Isolation of a toxin B-deficient mutant strain of Clostridium difficile in a case of recurrent C. difficile-associated diarrhea

Clostridium difficile-associated diarrhea (CDAD) recurs in approximately 15%-20% of patients after discontinuation of metronidazole or vancomycin therapy. Most recurrences are believed to be endogenous relapses due to the persistence of spores. However, there is evidence that reinfection with a different strain is a cause of recurrence. We report the case of a patient with a history of multiple episodes of C. difficile colitis. The patient, a 56-year-old female, has had 5 years of repeated recurrences, each shortly after discontinuing vancomycin therapy. During the course of these episodes, three isolates were cultured from her stools at different times. These isolates were analyzed for the presence of toxin A and B gene sequences and genotyped by means of arbitrarily primed polymerase chain reaction (AP-PCR). The original two isolates contained the toxin A and B genes, as determined by PCR, and were of the same AP-PCR type. During her last relapse, a C. difficile strain lacking at least a portion of the toxin B gene was isolated. AP-PCR analysis of this isolate showed a different DNA banding pattern from that of the previous isolates. A vancomycin susceptibility assay revealed a slight decrease in vancomycin activity as compared with that against the prior isolate. This case demonstrates two unique features: (1) recurrent infections can be due to reinfections and (2) toxin B mutants can possibly cause CDAD. This study also raises concerns about long-term vancomycin use and the development of resistance of C. difficile to vancomycin.

Isolation of various genotypes of Clostridium difficile from patients and the environment in an oncology ward

The epidemiology of Clostridium difficile-associated diarrhea (CDAD) is not well defined in nonepidemic situations because precise biotyping techniques have only recently become available. Arbitrarily primed polymerase chain reaction (AP-PCR) was used to determine strain identity of C. difficile isolates recovered on our oncology ward, at an incidence rate of 0.84%. Twenty-one strains of C. difficile, which were grouped into 18 different AP-PCR types, were isolated from patients' specimens. Forty-two C. difficile isolates recovered from the environment (33 toxigenic and 9 nontoxigenic) represented 9 different AP-PCR types. The most commonly found type, a toxigenic strain accounting for 29% of the environmental isolates, was widespread throughout the ward. None of the environmental types were found among the isolates from patients. Three patients' isolates were of the same AP-PCR type, and two of these patients had occupied neighboring rooms at the same time. The diversity of C. difficile isotypes suggests that endemic nosocomial CDAD is not necessarily clonally spread.

Detection of Cryptosporidium parvum DNA in human feces by nested PCR

Cryptosporidium parvum is a coccidian protozoan that causes diarrhea in humans, often chronic and severe in patients with AIDS. Conventionally, diagnosis is made by concentration of stools followed by acid-fast staining (AF) or immunofluorescent staining. The threshold of detection in human stool specimens by these methods may require the presence of 50,000 (immunofluorescent staining) to 500,000 (AF) oocysts per g of stool. In this study, a nested PCR assay was developed to detect C. parvum DNA directly from stool specimens. After extraction of DNA from formalinized stool, a 400-bp fragment of C. parvum DNA was amplified with two 26-mer outer primers. The amplicon from this reaction was amplified with a second primer pair. With these nested primers, a 194-bp DNA fragment was amplified and confirmed as C. parvum DNA by internal probing with an enzyme-linked chemiluminescence system. This PCR-based test allowed the detection of 500 oocysts per g of stool or 100 ng of C. parvum DNA. Studies indicate that the primers utilized are specific for the DNA of C. parvum. DNA sequences were also detected in stool specimens from 4 of 28 patients previously reported negative by AF. In summary, a rapid, sensitive, and specific assay for the detection of C. parvum directly from stool specimens has been developed. This test has the potential for detecting asymptomatic infection, monitoring the response to therapy, and detecting the organism in environmental sources.

Comparison of arbitrarily primed PCR with restriction endonuclease and immunoblot analyses for typing Clostridium difficile isolates

Arbitrarily primed PCR (AP-PCR) was used to genotype 26 clinical isolates of Clostridium difficile previously analyzed by immunoblotting (IB) and 20 isolates typed by restriction endonuclease analysis (REA) with HindIII. Two levels of differentiation were achieved with the AP-PCR approach by use of two different arbitrary primers. With the 19-mer arbitrary primer T-7 (first level of differentiation), a good correlation was found between IB and AP-PCR typing. Twenty isolates grouped into six IB types were separated into seven major AP-PCR types. These seven AP-PCR groups were further discriminated into 12 subtypes after genotyping with the arbitrary primer PG-05 (second level of differentiation). The remaining six isolates, all of different IB types, showed a unique and distinct DNA banding pattern with both of the arbitrary primers, T-7 and PG-05. Twenty isolates representing 20 REA types from 15 REA groups were resolved into 13 AP-PCR DNA profiles with the arbitrary primer T-7. A good correlation was found at this level of differentiation between the major REA groups, Y and M, and AP-PCR typing. While AP-PCR with this primer failed to differentiate isolates in REA groups J, G, R, and B, AP-PCR with PG-05 resolved these four isolates into four distinct AP-PCR types. In addition, one of three M strains and one of four Y strains displayed a slightly different DNA banding pattern by AP-PCR (with PG-05) from that of the other strains in the group. We conclude that AP-PCR is a rapid and sensitive method which not only complements other typing schemes but also may be a substitute and prove to be especially suited for immediate epidemiological tracking of nosocomial infections due to C. difficile.

[Seasonal variation in the ultrastructure and calcium uptake rate of cardiac sarcoplasmic reticulum in ground sqirrel]

The ultrastructure and calcium uptake rate of the cardiac sarcoplasmic reticulum (SR) was quantatively compared between the ground squirrels (Citellus dauricus) in hibernating and non-hibernating season. (1) In our ultrastructural investigation, OsFeCN post-fixation method was used to enhance the staining of SR, which made the SR structure more recognizable. (2) The results of morphometrical analysis demonstrated that the volume density of SR and lipid droplet in the cardio-myocyte was significantly higher (P < 0.01) in the hibernating animal than in the summer active one, and the subcompartment of SR with this difference was non-junctional SR. (3) The cardiac SR from hibernating ground squirrels had a higher (P < 0.01) calcium uptake rate as measured by the absorbence of arsenazo-III Ca2+ indicator, than that from autumn active ones. Altogether, our results suggested that the function of SR in the uptake of cytosolic calcium was enhanced in hibernating season, which may play an important role in the cold tolerance of myocardium of a hibernator.

Apparent outbreaks of Clostridium difficile-associated diarrhea in horses in a veterinary medical teaching hospital

Intestinal colonization with toxigenic strains of Clostridium difficile was documented in 9 of 10 horses with acute onset diarrhea in a veterinary medical teaching hospital, whereas a similar isolate was detected in only 1 of 23 other horses without diarrhea in the hospital. One horse with diarrhea was infected simultaneously with both C. difficile and Salmonella krefeld. Clostridium difficile was detected by fecal culture on selective medium, confirmed with a latex particle agglutination test, and identified as toxigenic by polymerase chain reaction amplification of toxin A and toxin B gene sequences. Using an arbitrarily-primed polymerase chain reaction, 6 distinct C. difficile isolates were detected in the feces of the 9 affected horses at the time of the outbreak of diarrhea.

Genomic fingerprinting of epidemic and endemic strains of Stenotrophomonas maltophilia (formerly Xanthomonas maltophilia) by arbitrarily primed PCR

Arbitrarily primed PCR (AP-PCR) was used to type 64 clinical isolates of Stenotrophomonas maltophilia from 60 patients and the hands of one nurse. Forty-seven different patterns were observed, most patients having isolates with unique genomic fingerprints. A single pattern, however, was obtained from six of eight patients involved in an intensive care nursery outbreak, confirming the suspected nosocomial transmission of this microorganism. This strain was also found in four other patients hospitalized at the same time but in different units. AP-PCR typing results had a good correlation with the 49 patterns obtained when the isolates were typed by contour-clamped homogeneous electric field gel electrophoresis. Although AP-PCR is slightly less discriminatory than contour-clamped homogeneous electric field gel electrophoresis, it offers several advantages and should be considered as a practical option for molecular typing during investigations of outbreaks.

Specific detection of Clostridium difficile toxin A gene sequences in clinical isolates

The polymerase chain reaction (PCR) was used to specifically detect toxin A gene sequences of Clostridium difficile in DNA isolated from human faeces. A set of oligonucleotide primers derived from the non-repetitive region of the toxin A gene was developed to amplify a 634-bp DNA fragment. All 28 cytotoxic strains of C. difficile, previously characterized by a toxin B-PCR assay, were positive for the presence of toxin A gene sequences. No amplification products were obtained from DNAs extracted from non-toxigenic strains, strains of C. sordellii, or C. bifermentans. In addition, amplification of DNA extracted from C. difficile 8864, a strain which does not produce toxin A, resulted in multiple bands which probed negative for toxin A gene sequences. DNAs extracted from nine stool specimens which were positive for toxin B by the cytotoxicity assay and by the toxin B-PCR assay were also positive in this assay. Toxin A gene sequences were detected in DNAs obtained from 4/11 stool specimens which were negative by the toxin B cytotoxicity assay. These four specimens were from patients who had a history of relapses due to C. difficile-associated colitis, and whose stools had previously been found to be positive by the toxin B-PCR test despite no detectable toxin B in the specimens. These data indicate a comparable degree of clinical sensitivity between these two toxin-gene PCR-based assays. This rapid, sensitive and specific assay may be useful not only in the diagnosis of C. difficile infections, but also in molecular studies of the toxin A gene in C. difficile strains.

Fecal shedding of Clostridium difficile in dogs: a period prevalence survey in a veterinary medical teaching hospital

The goal of this study was to determine the fecal prevalence of Clostridium difficile in dogs who were patients at a veterinary medical teaching hospital. Stool specimens collected from 152 dogs (in- and outpatients) were analyzed for the presence of C. difficile. An additional 42 stool specimens were collected and examined from dogs recently housed at local animal shelters. Following culture on selective medium, C. difficile was identified by a latex agglutination test, and the presence of the toxin A and B genes was determined individually by polymerase chain reaction. Clostridium difficile was isolated from the feces of 28 of the veterinary hospital patients (18.4%); isolates from 14 of these patients (50.0%) were toxigenic. Diarrhea was a clinical finding in 5 (35.7%) of the dogs carrying toxigenic isolates of C. difficile, whereas diarrhea was noted in only 2 of 14 dogs (14.3%) shedding nontoxigenic isolates. Three of 14 dogs (21.4%) shedding toxigenic isolates of C. difficile were receiving antibiotics at the time of stool collection, whereas 5 of 14 dogs (37.5%) shedding nontoxigenic strains of C. difficile were receiving antibiotics. The carriage rate of C. difficile was significantly higher for animals categorized as inpatients of the veterinary hospital. The carriage rate also provided evidence for an increased risk for fecal shedding with increasing age. Clostridium difficile was not isolated from any of the 42 dogs recently housed at local animal shelters. This study confirms the presence of toxigenic C. difficile in dogs at a veterinary teaching hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Genotyping of Clostridium difficile isolates

Arbitrarily primed polymerase chain reaction (AP-PCR) was used to genotype Clostridium difficile isolates from various sources. Four major molecular types were identified among strains from the American Type Culture Collection previously typed by serogroup and from isolates from patients at the University of California, Davis Medical Center, from a patient at a Utah institution, and from the environment. These groups contained subgroups that displayed, in addition to the common group bands, at least one unique band. Two strains isolated from patients at our institution had the same DNA banding patterns. These patients were hospitalized during the same period, raising the possibility of cross-infection through hospital contact or another common source. These results suggest that this AP-PCR approach will be useful in epidemiologic studies of C. difficile infections.

Diagnosis and monitoring of Clostridium difficile infections with the polymerase chain reaction

Toxigenic Clostridium difficile is the etiologic agent of pseudomembranous colitis. We have developed an assay system for the rapid direct detection of toxigenic C. difficile in human stool samples. After DNA extraction, polymerase chain reaction (PCR) amplification is undertaken with primers targeting specific sequences in the C. difficile 16S rRNA gene. Next, toxigenic strains of C. difficile are distinguished from nontoxigenic strains by PCR amplification of toxin A and/or B gene sequences. This study included 12 patients with C. difficile colitis, seven of whom had clinical relapses after discontinuation of vancomycin therapy. We detected toxigenic C. difficile in stools from four (57%) of these seven patients before relapse--at a time when no toxin B was detectable in stools and results of anaerobic culture were negative. The PCR assay is 100-fold more sensitive than anaerobic culture methods. The course of the infection in one patient (both during and after therapy) was monitored by the PCR technique. The multigene analysis approach permitted the detection of colonization with a nontoxigenic strain when this patient's relapses had cleared. This clinically applicable assay allows earlier detection of infection with toxigenic C. difficile. The result is more timely therapeutic intervention.

Specific detection of toxigenic strains of Clostridium difficile in stool specimens

Clostridium difficile is the infectious agent responsible for antibiotic-associated colitis. We report the use of the polymerase chain reaction technique to identify toxigenic strains of C. difficile in human stool specimens. A set of primers based on the nucleotide sequence of the toxin B gene, which amplified a 399-bp fragment from isolates producing toxin B, was designed. We examined 28 known toxigenic strains, which were all positive by this assay. DNAs from the nontoxigenic strains examined and from strains of Clostridium sordellii and C. bifermentans were not amplified with these primers. The sensitivity of this assay allowed us to identify as little as 10% toxigenic C. difficile cells in the presence of 90% nontoxigenic cells and to detect the toxin B gene in 1 pg of DNA from a toxigenic strain. DNAs extracted from 18 clinical stool specimens that were positive for toxin B by the tissue culture cytotoxicity assay were also positive by this assay. In addition, we detected toxin B sequences in DNA from 2 of 18 stool specimens that were negative for toxin B by the cytotoxicity assay. These two stool specimens were from patients who had a clinical pattern of colitis that was compatible with C. difficile causation. This rapid, sensitive assay will be useful for specific identification of toxigenic C. difficile and for revealing cases that are undetected by analysis of fecal samples for toxin B alone.