[Analysis of work-related musculoskeletal disorders among automobile manufacturing logistics workers in Guangzhou].

Objective: To investigate the occurrence of work-related musculoskeletal disorders (WMSDs) in logistics workers of automobile manufacturing enterprises in Guangzhou, and explore their potential categories and influencing factors, so as to provide basis for the prevention and control of WMSDs in logistics workers of automobile manufacturing enterprises. Methods: From April to May 2020, a convenient sampling method was adopted to select 1442 logistics workers in 2 automobile manufacturing enterprises in Guangzhou as the research objects. The incidence of WMSDs among them was investigated by using the Nordic Musculoskeletal Disorders Questionnaire, and the incidence pattern of WMSDs among the subjects was analyzed by the method of potential category analysis. Chi-square test and multiple logistic regression model were used to analyze the influencing factors of the disease. Results: The total prevalence of WMSDs was 42.9% (619/1442). The three parts with high prevalence of WMSDs were neck (23.5%, 339/1442), shoulder (21.3%, 307/1442) and lower back (19.1%, 275/1442). 69.0% (427/619) of the patients showed simultaneous disease in two or more sites. The subjects were divided into four latent groups by the analysis of latent categories: the group with multiple body parts (4.51%), the group with very low or no disease (70.39%), the group with shoulder and neck and upper back (11.37%), and the group with limbs and lower back (13.73%). Multivariate logistic regression showed that compared with the "very low or no disease group", the risk factors of multiple body parts of automotive logistics workers suffering from WMSDs mainly included: Working posture uncomfortable (OR=3.10, 95%CI: 1.44~6.70, P=0.004), often bend and turn (OR=2.36, 95%CI: 1.05~5.29, P=0.037), bend your knees homework for a long time (OR=2.29, 95%CI: 1.17~4.47, P=0.015) ; Working posture uncomfortable (OR=2.26, 95%CI: 1.51~3.38, P<0.001), bending the neck (OR=1.68, 95%CI: 1.03~2.74, P=0.036), neck minister time keep the same position (OR=1.81, 95%CI: 1.22~2.67, P= 0.003) It is a risk factor for shoulder, neck and upper back WMSDs; Risk factors for limb-lower back WMSDs include: Length > 10 years (OR=2.16, 95%CI: 1.24~3.78, P<0.001), the working position uncomfortable (OR=2.38, 95%CI: 1.63~3.48, P<0.001), bending the neck (OR=1.66, 95%CI: 1.03~2.68, P=0.039) . Conclusion: The prevalence rate of WMSDs among logistics workers in automobile manufacturing enterprises is high, which has obvious characteristics of classification and comorbis, and is closely related to individual characteristics such as sufficient rest time and working posture of workers.

[Analysis on prevalence status and the influencing factors of work-related musculoskeletal disorders among workers in an automobile manufacturing enterprise in Guangzhou City].

Objective: To analyze the detection and influencing factors of work-related musculoskeletal disorders (WMSDs) of workers in an automobile manufacturing enterprise in Guangzhou City. Methods: In April 2020, a total of 7065 workers of an automobile manufacturing enterprise in Guangzhou City were selected as research subjects using cluster sampling method. The Nordic Musculoskeletal Questionnaire (NMQ) was used to investigate the detection of WMSDs. Multiple logistic regression analysis was used to analyze the influencing factors of WMSDs. Results: The detection rate of WMSDs was 43.9% (3102/7065) , among which the detection rate of multiple WMSDs was 31.4%. The detection rates of WMSDs in different parts from high to low were as follows: neck (24.5%) , shoulder (21.1%) and ankle (20.1%) . Multivariate logistic regression analysis showed that working experience of 3-8 years, >8 years, age>30 years old, repetitive work every day, multiple repetitions per minute, uncomfortable work posture, frequent overtime work and lack of staff in the department were risk factors for multi-site WMSDs (P<0.05) . Adequate rest time was a protective factor for multi-site WMSDs (P<0.05) . Conclusion: The detection rates of WMSDs in neck, shoulder, ankle, and multisite in automobile manufacturing enterprise are relatively high. The primary risk factors include adverse ergonomic factors and unreasonable organization of labour factors, optimize the work breaks can effectively reduce the risk of disease, effective ergonomic interventions should be carried out to prevent the occurrence of WMSDs among workers in the automobile manufacturing industry.

The Diagnostic Value of Serum ST8SIA6-AS1 as Biomarker in Hepatocellular Carcinoma.

BACKGROUND: Long noncoding RNA (lncRNA) is a promising serum biomarker in cancer diagnosis. However, literature on the diagnostic value of the lncRNA for hepatocellular carcinoma (HCC) is scant. METHODS: The expression of ST8SIA6-AS1 in serum and HCC cell lines was detected by real-time PCR (RT-PCR). We then analyzed the relationship between clinicopathological characteristics and serum ST8SIA6-AS1 expression. In addition, we performed the receiver operating characteristic (ROC) curve and area under curve (AUC) analyses to determine the diagnostic ability of serum ST8SIA6-AS1. RESULTS: Our data demonstrated an up-regulation of ST8SIA6-AS1 in 77 HCC patients and HCC cell lines. Besides, clinicopathological analysis revealed that ST8SIA6-AS1 corresponds with tumor stages and metastasis, thus might be used for monitoring the HCC progress. Importantly, the ROC analysis demonstrated that ST8SIA6-AS1 yields a superior diagnostic ability. Compared with α-fetoprotein (AFP) alone, a combination of ST8SIA6-AS1 and AFP may achieve more reliable diagnostic results. CONCLUSIONS: Together, our results demonstrate that serum ST8SIA6-AS1 is a promising serum diagnostic bio-marker for HCC.

[Application of two risk assessment methods in ceramic manufacturing enterprises].

Objective: To explore the applicability of Singapore semi-quantitative assessment method and international committee on mining and metals occupational health risk assessment method in occupational health risk assessment of ceramic enterprises. Methods: From March 2017 to May 2018, A ceramic enterprise was selected for the investigation and testing of occupational health, and the risk assessment of the occupational-disease-inductive factors in the workplace was conducted by the semi-quantitative assessment method of Singapore and the occupational health risk assessment method of the international committee on mining and metals. Results: The occupational-disease-inductive factors in the production process of this ceramic enterprise mainly include silicon dust, noise, high temperature, carbon monoxide, carbon dioxide and so on. The two risk assessment methods were applied to assess the risk of occupational-disease-inductive factors in the workplace, and the results showed that the high risk level was 16.67%, the medium risk level was 63.33%, and the low risk level was 20.00%. The risk level of silicon dust is from low risk to high risk. Conclusion: The semi-quantitative assessment method and the occupational health risk assessment method of the International Commission on Mining and Metals are simple to operate and practical, and are suitable for the assessment of occupational hazards in ceramic enterprises.

[Study on determination of ethylal in workplace air by gas chromatography].

Objective: A solvent desorption-gas chromatography method for determination of ethylal in workplace air has been established. Methods: Ethylal in workplace air was collected by activated carbon tube and desorbed with carbon disulfide, and the desorption solutions were analysed by capillary column GC with FID detector. Results: The method presented a good linearity in the range of 0.87~34 800.00 mg/L of ethylal in the standard solution, with the correlation coefficient being r=0.999 7. The limit of detection and the limit of quantification of this method were respectively 0.20 mg/L and 0.80 mg/L, and the minimum detectable concentration and the minimum quantification concentration of this method were respectively 0.17 mg/m(3) and 0.60 mg/m(3) per 1.50 L of air.The within-run precision of the method was 2.93%-6.20%, and the between-run precision 3.67%-6.44%. The desorption efficiency between 94.22%-97.27%. Ethylal in activated carbon tube could be kept at least 7 days at room temperature without significant loss. Conclusion: The method could be used for determination of ethylal in workplace air.

Assessment of mouth-level exposure to tobacco constituents in U.S. snus consumers.

INTRODUCTION: When assessing the health risks associated with different tobacco product categories (e.g., combustible and noncombustible), it is important to understand exposure. Snus, a smokeless tobacco product with lower levels of most tobacco-related toxicants than cigarette smoke, has been recently introduced in the United States. The objective of this study was to evaluate the mouth-level exposure (MLE) to selected tobacco constituents from snus by adult consumers of Camel SNUS (CSNUS). METHODS: For 7 days, 53 adult CSNUS consumers used their usual brand styles ad libitum, collecting their snus pouches after use. The collected pouches and unused product were analyzed for nicotine, N'-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N'-nitrosoanabasine (NAB), N'-nitrosoanatabine (NAT), benzo[a]pyrene (B[a]P), arsenic, cadmium, chromium, lead, and nickel. MLE was estimated using the difference between the constituent amounts in the used and unused snus products. RESULTS: CSNUS consumption averaged 3.3 pouches/day or approximately 1.98 g/day. Mean nicotine MLE was 2.8 mg/pouch or 9.4 mg/day. Mean MLE to total tobacco-specific nitrosamines (TSNAs: NNK, NNN, NAB, and NAT) was 171.5 ng/pouch or 527.7 ng/day. B[a]P MLE averaged 0.2 ng/pouch or 0.68 ng/day. CONCLUSIONS: This study is the first to report snus MLE under normal conditions of use in a group of adult, U.S. snus consumers. On average, approximately 60%-90% of the amounts of nicotine, TSNAs, and B[a]P initially present in a snus pouch remained in the pouch after use by snus consumers in this study. The results from this study provide a preliminary assessment of exposure to constituents present in snus, which is potentially useful in risk assessment.

Severe hemodynamic instability during elective surgery for a patient with a giant pheochromocytoma: A case report.

INTRODUCTION: We present a patient with a huge pheochromocytoma who ran a stormy intraoperative course. PRESENTATION OF CASE: A 57-year-old woman underwent elective open surgery for a giant pheochromocytoma (16 × 15 × 10 cm) after adequate preoperative medical preparation. The patient developed severe hypertension on tumor mobilization followed bylife-threatening hypotensionwhen the tumor was removed. The hemodynamic instability was successfully managed. Histology showed a pheochromocytomawith tumor-free resection margins. The patient fully recoveredandthe hypertension completely resolved after the operation. DISCUSSION: This is a rare and educational case report on a patient with a huge pheochromocytoma who was successfully managed by a multidisciplinary team of specialists. CONCLUSION: Pheochromocytoma should be resected if technically possible. A multidisciplinary team approach is required for proper management.

Factors associated with maternal cell contamination in amniocentesis samples as evaluated by fluorescent in situ hybridization.

OBJECTIVE: To determine which patient- and procedure-related factors contribute to maternal cell contamination in uncultured amniocentesis fluid. METHODS: One hundred thirty amniotic fluid (AF) samples were obtained by three operator groups: maternal-fetal medicine faculty (n=50), general obstetrician gynecologists (n=50), and obstetrics and gynecology residents supervised by maternal-fetal medicine faculty (n=30). These groups were designated "most," "intermediate," and "least experience," respectively. Study variables were recorded at the time of the procedure. Amniotic fluid cells from male fetuses underwent fluorescent in situ hybridization. Maternal cell contamination was calculated by analyzing 100 cells and determining the number of XX and XY cells. A control system was created to validate the methods used for AF processing and cell counting. RESULTS: Median maternal cell contamination was 2.0%. Maternal cell contamination did not vary with body mass index (r=-.13, P=.14), gestational age (r=.08, P=.35), or placental location (P=.55). Maternal cell contamination was significantly elevated with placental penetration (6.0% compared with 1.0%, P < .001), two passes (27.5% compared with 2.0%, P=.002), blood-tinged fluid color (14.0% compared with 2.0%, P < .001), and operator inexperience ("intermediate experience" compared with "most experience," 4.5% compared with 1.0%, P=.026). Maternal cell contamination did not differ between the "most experience" and "least experience" groups (1.0% compared with 2.0%, not significant). Concordance between detected and actual maternal cell contamination in the control system was extremely high (concordance coefficient=0.98, P=.008), confirming the validity of the techniques used. CONCLUSION: Our techniques of cell counting and maternal cell contamination calculation are accurate. Maternal cell contamination is increased with placental penetration, two passes, and operator inexperience. However, with expert supervision, inexperienced physicians can perform amniocentesis without an increase in maternal cell contamination.

Cerebellar evoked potential elicited by stimulation of C-fiber in saphenous nerve of cat.

Stimulation of the saphenous nerve above C-fiber threshold strength evoked a field potential which consisted of an early component with latency of 11.8 +/- 3.5 ms and a late component with latency of 312.1 +/- 17.5 ms on the cerebellar cortex. After the A-fibers in saphenous nerve were blocked by the polarizing current selectivity, the stimulation at C-fiber suprathreshold elicited a C-fiber cerebellar evoked potential (C-CEP) with latency of 134.2 +/- 18.4 ms. C-CEP had the maximal amplitude on the vermian lobule VI of the contra- and ipsilateral cerebellar cortex and its phases reversed in the deep layer of this area. It was suggested that the selective C-fiber input could reach the cerebellar cortex and elicit a characteristic evoked potential. However, when A- and C-fiber inputs were elicited simultaneously, C-CEP might be inhibited by the A-fiber input.

[Simple spike response of cerebellar Purkinje cells to stimulation of C-fiber in saphenous nerve].

Simple spike of cerebellar Purkinje cells (PC-SS) was recorded with microelectrode. In the NCCVF (normalized cross-covariance function) histogram, spontaneous PC-SS does not show obvious peak. When the saphenous nerve is stimulated at lower intensities, which elicits the A-fiber input only, the discharge response (A-CED) consists of an early component with a latency of 16.7 +/- 0.9 ms and a late component with a latency of 270.8 +/- 12.8 ms. After A-fibers are blocked selectively by polarizing current, the stimulation at a suprathreshold strength for C-fiber evokes a characteristic response (C-CED) with a latency of 142.4 +/- 4.3 ms. However, the C-CED can not be evoked by the inputs of A- and C-fiber simultaneously. In NPSDF histogram, the spontaneous activities of PC-SS can be divided into two groups, the high and the low peak group. The high peak group (n = 15) has a peak energy value of 15.7 +/- 4.7 x 10(-3) and peak frequency of 4.07 +/- 1.69 Hz. A-fiber input causes an increase of the peak value, while C-fiber input causes a decrease. The low peak group (n = 16) has a peak energy value 8.4 +/- 1.4 x 10(-3) and peak frequency of 3.67 +/- 2.90 Hz. Both A-fiber and C-fiber inputs cause an increase of the peak value, but the effect of A-fiber input was more prominent. The results show that the pure C-fiber input can reach the cerebellar PC and elicit characteristic simple spike response.

[Influence of stimulation of cerebral anterior lateral association area on cortical potentials evoked by C-fiber inputs in saphenous nerve].

The effect of stimulation of cerebral anterior lateral association area (ALA) on evoked potentials recorded in the primary somatosensory cortex (SI), elicited by C-fiber inputs of saphenous nerve (C-CEP) was investigated in cats anesthetized with chloralose and immobilized by Flaxedil. Following 1 min electric stimulation of ALA (0.1 mA, 100 Hz, duration 0.2 ms), the amplitudes of C-CEP were obviously decreased, indicating that ALA had an inhibitory effect on C-CEP. In order to explore the neural pathway underlying the inhibition of C-CEP by ALA stimulation, a vertical section between ALA and SI was made. It was shown that the inhibition of C-CEP produced by ALA stimulation was reduced considerably and the time course of the inhibition was shortened after the section. Moreover, the ALA stimulation-produced inhibition was also blocked partially 7 min after the intraventricular injection of naloxone (25 micrograms/50 microliters). The results suggest that ALA may exert an inhibitory effect on C-CEP, which is mediated by endogenous opiate like substances and through the nervous connection between ALA and SI. The cerebral association area may play a role in the modulation of C-CEP.

[Effect of stimulating midbrain periaqueductal gray on the electrical response of somatosensory cortex to C-fiber input in cats].

The electrical responses of the somatosensory cortex (C-CEP) and spinal cord (C-SSP) to C-fiber inputs could be markedly inhibited by stimulating the periaqueductal gray (PAG), and the inhibition on C-CEP was greater than that on C-SSP. After application of cyproheptadine on the dorsal surface of the spinal cord, PAG stimulation could still inhibit C-CEP, but not C-SSP. It was suggested that PAG might inhibit C-CEP through ascending as well as descending pathways. After blocking the descending inhibitory pathway by cyproheptadine i.v. injection, cyproheptadine and naloxone could antagonize the inhibitory effect of PAG stimulation on C-CEP, indicating that endogenous opiate-like substance and serotonin might play an important role in the transmission of the ascending inhibitory pathways from PAG.

[Electric responses evoked by C-fiber input from saphenous nerve in cat cerebellar cortex].

When the A-fibers of the saphenous nerve were stimulated at a lower intensity which elicited the A-fiber input only, an evoked potential (A-CEP) which consisted of an early component with latency of 11.8 +/- 3.5ms and a late component with latency of 312.1 +/- 17.5ms could be recorded on the surface of the cerebellar cortex in cat. When A- and C-fibers were activated by stimulation at the strength of C-fiber suprathreshold, the latency and configuration of the evoked potential had no significant difference from one of the A-CEP. After A-fibers were blocked by the polarizing current, stimulation at the strength of C-fiber suprathreshold could evoke a characteristic C-CEP with latency of 134.2 +/- 18.4ms. In general, C-CEP whose maximal amplitude was recorded on the vermain lobule VI was a positive-negative potential and its phases were reversed in the deep layer of the cerebellar cortex. C-CEP had a smaller amplitude, a longer latency and a lower following frequency than A-CEP had. In comparison with A-CEP, C-CEP had a high susceptibility to the morphine. The results showed that C-CEP which was evoked by the selective C-fiber input and generated in the cerebellar cortex seemed to be a response to the information of the slow pain input. It was suggested that C-fiber input could reach the cerebellar cortex and elicited an evoked potential. When A- and C-fiber were activated at the same time, C-CEP might be inhibited by the A-fiber input.

[Single channel properties of NMDA receptors in cortical neurons].

The cell-attached and inside-out configurations of the patch-clamp techniques were used to investigate single channel properties of NMDA receptors in cultured intact neurons mechanically isolated from rat cereberal cortex. Recordings were made in Mg(2+)-free solutions. A channel, with a conductance of 35 pS was studied in detail with either NMDA or L-aspartate in the patch pipette. NMDA channels were permeable to Na+ K+, but not to Cl-, the mean open times and open probabilities of these channels were decreased with increasing hyperpolarization. Distributions for the open times, closed times and burst durations required two-component fits. Channel openings were suppressed by APV. When Mg2+ was included in the pipette, the mean open times were significantly diminished in a concentration- and voltage-dependent manner. Decreasing the bath temperature prolonged channel open times and decreased current amplitudes. The results indicate that there is an intrinsic voltage dependence of NMDA channel kinetics in the intact neurons, suggesting that the normal function of the NMDA channel may be dependent on some intracellular biochemical processes.

[ATP-activated single ion channel and its properties in cerebral cortical neurons of neonatal rat].

In the present study, single channel currents were recorded from single neurons dissociated from the cerebral cortex of neonatal SD rat by the cell-attached and inside- out modes of patch clamp technique. ATP-activated channels with a conductance of 32 pS were often recorded and permeable to Na+, K+ and Cs+, but not to Cl-. Most of open time distribution histograms were fitted by two exponential components and few by one, whereas closed time distribution histograms were fitted by two exponential components. Both mean open time and open probability were independent of membrane potential, but the latter increased with increasing ATP concentration. The channel activity was recorded only in the presence of pipette solution containing ATP, and its conductance and open probability were not affected by ACh N-receptor antagonist hexamethonium and mecamylamine. It is suggested that ATP-activated ion channels probably exist in the cerebral cortical neurons of neonatal rat.

[Effects of 17 beta-estradiol on delayed rectifier potassium channels in hippocampal pyramidal neurons of the rat].

In the present study, both cell-attached and inside-out patch-clamp techniques were used to detect the effects of 17 beta-estradiol (E2) on 42 pS delayed rectifier potassium channels in acutely dissociated hippocampal neurons of new-born SD rats. The results indicated that after application of 1.0 and 10.0 nmol/L E2, the open probabilities of K+ channels were decreased from (67.4 +/- 18.2)% to (41.2 +/- 12.5)% and from (56.3 +/- 15.8)% to (13.2 +/- 12.6)% respectively, the open frequencies were reduced from (43.40 +/- 6.7) Hz to (27.68 +/- 9.1) Hz and from (38.19 +/- 10.1) Hz to (15.79 +/- 3.5) Hz respectively. Meanwhile, there was a shortening of the mean open time and a lenghtening of the mean close time of the channels. The above results suggest that E2 has suppressive effects on the activities of the channels, which might be exerted through a direct action on the cellular membrane.

[Spectrum analysis of cat si neurone discharges].

Spontaneous firing and the discharges evoked by A- and/or C-fiber inputs (A-ED, C-ED, AC-ED) of saphenous nerve were recorded in the somatosensory cortical (SI) neurons (n = 128) of the cats anesthetized with chloralose and paralysed by gallamine. Normalized power spectrum density function (NPSDF) was used to analyse the neuron discharges. The results showed that 1) all the NPSDFs for the spontaneous discharges were single-peak with a peak frequency of 3.91 +/- 1.63 Hz (spontaneous rhythm) and a peak value of 0.0154 +/- 0.0045; 2) the NPSDFs of A-ED showed a single peak (peak value 0.021 +/- 0.0054) and an overlapped double-peak (with spontaneous discharge) or a separate multi-peak (without spontaneous discharge); 3) the NPSDFs of C-ED showed a single peak (peak value 0.020 +/- 0.007) or a separate double-peak; 4) the NPSDFs of AC-ED have two patterns: a single peak (peak value 0.023 +/- 0.004) and an overlapped multi-peak. It is suggested that A-fiber input can potentiate the rhythms of the spontaneous discharge and induce specific rhythm; that C-fiber input can potentiate the spontaneous rhythm and induce characteristic C-rhythm. It is also observed that both spontaneous rhythm and evoked rhythm affect each other; that the evoked rhythms by A-fiber and C-fiber inputs also affect each other.

[Effect of electrical stimulation of second somatosensory cortex on the response of primary somatosensory cortex to C-fiber inputs].

When the projecting point of saphenous nerve in second somatosensory cortex (S II) of cat was stimulated, the evoked potentials elicited by C-fiber inputs of saphenous nerve recorded in the primary somatosensory cortex (C-CEP) might be either inhibited or facilited according to whether the superficial and/or the deeper layer of the cortex was stimulated. The inhibition was expressed as a decrease of amplitude and prolongation of latency of C-CEP; while the facilitation, as an increase of amplitude and duration of C-CEP. When the superfaicial layer of S II was stimulated by weaker current, both inhibitory and facilitatory effects could be observed, but only inhibitory effect was observed, when the deep layer was stimulated. With the same intensity of stimulation, inhibitory effect was more pronounced when the deep layer rather than the superficial layer was stimulated. It is suggested that S II may play a role in the modulation of C-CEP of S I.

[Changes of K+ channel current in cerebellar cortical neuron of apoptosis induced with H2O2].

The neurons dissociated from the cerebellar cortex of neonatal SD rat were cultured, while the growth of non-neuron cells were suppressed by Ara-c. Apoptosis of the neurons were induced with H2O2. The changes of Ik were studied during apoptosis using the patch clamp technique in cell-attached configurations. The results are as follows: (1) the Ik amplitudes of the neurons were lower than that of normal at various corresponding clamp voltages; (2) the conductances, mean open time, open probability, long and short opening time constants were all lower, as compared with normal neurons. All these results indicate that the activities of K+ channels on cerebellar neurons decrease during apoptosis.

[Effect of pregnenolone sulfate on delayed rectifier K+ channel in pyramidial neuron of cerebral cortex].

Recent studies have shown that endogenous brain metabolites of steroids may exert important nongenomic modulatory effects on neuronal mechanisms. In this work the effect of pregnenolone sulfate (PS) on delayed rectifier K+ channel (IK) was studied in acutely dissociated rat cerebral cortical pyramidial neurons by means of cell-attached and inside-out patch clamp techniques. The open probability and mean open time of the IK channels were increased by PS in a concentration-dependent manner over the range of 30-100 mumol/L. but without changing the IK amplitude.