[Study on risk factors of mycobacterium tuberculosis infection among health workers in medical institutions]

Objective: To understand the infection status of mycobacterium tuberculosis among health workers in tuberculosis designated medical institutions and explore the risk factors of infection. Methods: From September 2021 to June 2022, a questionnaire survey was conducted among health workers in relevant departments of 4 tuberculosis designated medical institutions by cluster stratified sampling, including the implementation of hospital infection control measures in medical institutions and occupational exposure of medical staff to mycobacterium tuberculosis. Peripheral blood interferon gamma release assays (IGRAs) and lung imaging examination were performed to determine the mycobacterium tuberculosis infection. Factors with statistical significance in univariate analysis were included in multivariate logistic regression to analyze the risk factors of mycobacterium tuberculosis infection. Results: A total of 657 people completed the lung imaging examination and questionnaire, of which 654 people had peripheral blood IGRAs detection, and the latent infection rate of tuberculosis was 39.45% (258/654) . Univariate analysis showed that age, sex, marital status, economic income, occupational category, professional title, length of service, and other variables had statistical significances in tuberculosis latent infection (P<0.05) . In terms of personal health status, there were statistically significant differences in the distribution of health workers in terms of their tuberculosis history, tuberculosis history of their immediate family members, previous tuberculin skin test (TST) (P<0.05) . Multivariate analysis showed that there were four risk factors related to tuberculosis, including professional title (X(1)) , years of tuberculosis related works (X(2)) , tuberculosis history (X(3)) and previous TST (X(4)) . The regression equation of the probability of tuberculosis among health workers was y=-1.920+0.246X(1)+0.046X(2)+1.231X(3)+0.478X(4). Conclusion: The latent infection rate of tuberculosis among health workers in tuberculosis designated medical institutions is high. It is necessary to strengthen the management of infection control, carry out regular screening, enhance the self-protection awareness of health workers, and reduce their exposure to mycobacterium tuberculosis and infection risk.

[Study of bone mineral density and serum bone turnover markers in newly diagnosed systemic lupus erythematosus patients]

OBJECTIVE

To investigate the changes of bone mineral density (BMD) and serum bone turnover factor in newly diagnosed systemic lupus erythematous (SLE) patients.

METHODS

Eighty newly diagnosed SLE patients and 80 age and gender matched healthy controls were enrolled. None of the SLE patients had ever received glucocorticoid, immunosuppressive agents or vitamin D. BMD was measured at radius,lumbar spine and hip by dual X ray absorptiometry (DXA). Bone turnover markers including serum levels of tartrate-resistant acid phosphatase 5b (TRAP5b),bone alkaline phosphatase (BAP) and 25-hydroxy vitamin D3 (25-OH-VD3) were measured by enzyme-linked immunosorbent assay (ELISA). Logistic regression was employed to analyze the risk factors associated with decreased BMD.

RESULTS

Mean age of the SLE patients was (32.8±12.4) years, and 85% were female, none of whom were post-menopausal. BMD was significantly reduced in all the measured sites, compared with the healthy controls. Sixteen (20%) of the patients were osteopenic in at least one site measured locations. The serum levels of 25-OH-VD3 were markedly reduced in the newly diagnosed SLE patients than those of the normal controls [(46.1+12.3) nmol/L vs. (25.4+11.2) nmol/L, P<0.001)]. The serum levels of 25-OH-VD3 in the SLE patients with nephritis were much lower than those without nephritis (P=0.04). A significant negative correlation was demonstrated between the serum concentration of 25-OH-VD3 and the disease activity scores as measured by SLE disease activity index (SLEDAI) (r=-0.3,P=0.001). The serum TRAP5b concentration was positively correlated with SLEDAI (r=0.435,P=0.003). Age (P=0.058) and SLEDAI (P=0.085) were probably associated with decreased BMD in Logistic regression analysis.

CONCLUSION

The study showed reduced BMD in untreated SLE patients. The role of chronic inflammation was of probable importance in bone metabolism.

[Comparison of bone destruction markers in patients with gouty arthritis under different musculoskeletal ultrasonic manifestations]

Objectives: To observe the correlation between the different ultrasonic manifestations of gouty arthritis and the indexes of bone destruction (Dickkopf-1, RANKL), in order to further explore the role of musculoskeletal ultrasonography in the diagnosis and monitoring of gouty arthritis. Methods: 160 cases of gouty arthritis from clinic of the Department of Rheumatology of Peking University People's Hospital between July 2016 and June 2017 were recruited in this study. These patients were examined by musculoskeletal ultrasonography (bilateral first metatarsophalangeal joints, bilateral ankle joints and bilateral knee joints). Grouping was based on ultrasound features of joints. Group A showed no aggregate .Group B showed aggregate and double contour signs. Group C showed tophus and bone erosion. Serum concentrations of Dickkopf-1 and RANKL were measured. The correlations of Dickkopf-1 or RANKL and clinical/laboratory parameters were analyzed. Results: (1)There was a significant difference in Dickkopf-1 concentration between the three groups(P<0.001). And the group C[(1 722.2±482.7)ng/L]was higher than the group B[(1 309.3±496.4)ng/L](t=4.418, P<0.001), and the group B was higher than group A[(807.9±373.8)ng/L](t=6.137, P<0.001). (2)There was a significant difference in RANKL concentration between the three groups (P<0.001). And the group C[(0.78±0.47)ng/L]was higher than the group B[(0.35±0.29)ng/L](t=5.456, P<0.001), and the group B was higher than group A[(0.10±0.09)ng/L](t=6.923, P<0.001). (3)The level of Dickkopf-1 was associated with the disease duration(r=0.430, P<0.001), and the level of RANKL was associated with the disease duration(r=0.359, P<0.001). Conclusion: Aggregates, double contour signs, tophus and bone erosion can be observed in the ultrasonic examination of gouty arthritis. And the longer the duration of the disease, the more likely the extent of bone destruction is. Joint ultrasound can be the first imaging examination for the extent of joint involvement in gouty arthritis. And the longer the duration of the disease, the more likely the extent of bone destruction is. Musculoskeletal ultrasonography can be the preferred imaging method for detecting the extent of joint involvement in gouty arthritis.

Tensile properties, tension-tension fatigue and biological response of polyetheretherketone-hydroxyapatite composites for load-bearing orthopedic implants

Polyetheretherketone-hydroxyapatite composites were developed as alternative materials for load-bearing orthopedic applications. The amount of hydroxyapatite (HA) incorporated into the polyetheretherketone (PEEK) polymer matrix ranges from 5 to 40 vol% and these materials were successfully fabricated by injection molding. This study presents the mechanical and biological behavior of the composite materials developed. It was found that the amount of HA in the composite influenced the tensile properties. Dynamic behavior under tension-tension fatigue revealed that the fatigue-life of PEEK-HA composites were dependent on the HA content as well as the applied load. The biological responses of PEEK-HA composites carried out in vivo verified the biocompatibility and bioactive nature of the composite materials.

Hard metal lung disease--the first case in Singapore

INTRODUCTION

We report the first case of hard metal lung disease in Singapore and the occupational investigative work and control measures that were undertaken.

CLINICAL PICTURE

A 38-year-old machinist in the tool manufacturing industry presented with exertional dyspnoea and cough. Chest X-ray revealed bilateral reticulonodular infiltrates with honeycombing. High resolution computed tomography scan of the thorax confirmed the presence of interstitial fibrosis. Open biopsy of the lung showed features of pneumoconiosis. Particle induced X-ray emission (PIXE) analysis, a relatively new elemental analysis technique, performed on the lung biopsy specimen confirmed the presence of tungsten and titanium; and he was diagnosed to have hard metal lung disease. Microbiologic, serologic and histologic investigations excluded an infective cause. Serial pulmonary function tests on follow-up showed no progression. He presented with haemoptysis 10 months later and was diagnosed to have tuberculosis on the basis of positive sputum and bronchoalveolar lavage cultures for Mycobacterium tuberculosis complex.

TREATMENT

Preventive measures and permanent transfer to non-cobalt work were instituted.

OUTCOME

The interstitial fibrosis appears to have stabilised.

CONCLUSION

The diagnosis of hard metal lung disease must be considered in a worker exposed to cobalt presenting with interstitial fibrosis.

IS element ISXC6 of Xanthomonas campestris pv. campestris

An insertion sequence element, ISXC6, was isolated from Xanthomonas campestris pv. campestris 17 (Xc17). Sequence analysis showed that it is 1,500 bp long and has 20-bp perfect inverted repeat ends. Upon transposition, a direct repeat TAATTC was generated, flanking this IS. No significant homology was observed between this sequence and other sequences in database. Results of Southern hybridization showed that multiple copies of ISXC6 were present in 7 strains of Xanthomonas examined.

Monitoring statistics which have increased power over a reduced time range

The problem of monitoring trends for changes at unknown times is considered. Statistics which permit one to focus high power on a segment of the monitored period are studied. Numerical procedures are developed to compute the null distribution of these statistics.

The relationship between systolic anterior motion of the mitral valve and the left ventricular outflow tract Doppler in hypertrophic cardiomyopathy

In an attempt to investigate the role of left ventricular blood outflow in the generation of systolic anterior motion (SAM) of the mitral valve in patients with hypertrophic cardiomyopathy, we precisely analyzed the temporal relation of SAM and the left ventricular outflow tract (LVOT) systolic Doppler events obtained at the maximal mitral-septal apposition or equivalent area in eight patients with severe SAM, in five patients with mild/moderate SAM, and in seven patients with no SAM, using M-mode and pulsed Doppler echocardiography; the results were compared with those in 10 normal subjects. In all 13 patients with SAM, the timing of SAM generation corresponded to the LVOT Doppler events either between the onset of SAM and the onset of Doppler (r = 0.834, p less than 0.0001) or between the peak of SAM and the peak of Doppler (r = 0.836, p less than 0.0001). The excursion rate of the development of SAM showed a correlation with the LVOT blood outflow acceleration (r = 0.828, p less than 0.0001). The timing of SAM resolution also correlated with the Doppler events, either between the offset of SAM and the offset of Doppler (r = 0.795, p less than 0.001) or the end of SAM and the end of Doppler (r = 0.859, p less than 0.0001). The LVOT blood outflow deceleration showed a correlation with the regression rate of SAM (r = 0.668, p less than 0.013). The LVOT blood outflow acceleration was significantly higher in patients with severe SAM than in patients with mild/moderate SAM or no SAM. This study suggests that the high LVOT blood outflow acceleration in early systole possibly plays an important part in the generation of the Bernoulli pressure drop and results in anterior motion of the mitral valve. At mid-systole, a drag force and/or suction effect of pressure drop produced by continuous outflow blood may sustain the anterior motion of the mitral valve. At late systole, as the blood flow decelerates, the regression of SAM then occurs.

[Hair zinc and copper concentration in patients with epilepsy]

The concentration of zinc and copper in the hair of 55 patients with epilepsy was determined. The hair copper levels in patients with epilepsy were significantly lower than those in the normal control group (P less than 0.001). The hair zinc levels in female patients were significantly lower than those in the normal control group (P less than 0.05). In the following patients: (1) with generalized seizure, (2) with the disease course 0-5 years, (3) EEG showed heavy or middle abnormality, (4) had epileptic attacks within one year before the sample was taken, the zinc levels were also significantly lower compared with controls (P less than 0.05). Antiepileptic drugs had more effect on hair zinc than on copper. The increase in the hair zinc and copper and zinc: copper ratio seems to show the efficiency of drugs.

The effect of autocorrelated errors on change-detection statistics

In this paper, regression models with error terms generated by lower order ARMA schemes are analyzed. Methods are discussed for estimating the parameters of the regression coefficients and the ARMA processes. The problem of detecting changes in the regression parameters is considered. A change-detection statistic proposed by MacNeill (1978) for regression problems is modified for application to ARMA processes. The effect of autocorrelated errors on this statistic is briefly discussed.

Strontium/calcium ratio analysis of molluscan shells in Singapore waters using the X-ray fluorescence technique

The Sr/Ca ratios in molluscan shells in Singapore waters were measured using the X-ray fluorescence (XRF) technique. Our results show that the Sr/Ca ratio varies greatly among different species. However, within the same species, this ratio is practically the same for samples collected from sites close together but varies significantly for samples from sites far apart. Furthermore, this study shows that whole shell analysis using the XRF technique is simple and quick and that its application to environmental monitoring seems feasible.