[Exploration and application of occupational disease risk assessment model based on information diffusion theory].

Objective: To research build a kind of occupational disease risk assessment model which provides scientific basis for prevention and control of occupational diseases. Methods: Based on the principle of information diffusion, this paper uses spread function to extend the incomplete gathered information, establishes the mapping relationship between observation samples and risk probability distributions, and constructs the occupational disease risk assessment model, to analyzes the risk data of occupational disease reported cases in Guangdong Province in the past five years. Results: Through evaluation analysis, every year, 200-300 cases of pneumoconiosis probability is 67.77%, 100-200 cases of occupational poisoning probability is 68.52%, 20-40 cases of occupational cancers probability is 71.62%, each year, the incidence of occupation otorhinolaryngology and oral diseases in 200 cases was 62.23%. Conclusion: A model of occupational disease risk assessment based on information diffusion theory is constructed, the evaluation result is basically consistent with the actual situation of occupational disease, which can provide reference for occupational disease prevention and control.

[Diagnostic value of two immunoassays for detecting heparin/PF4 complex antibodies in heparin-induced thrombocytopenia].

Objectives: To assess the diagnostic values of latex immunoturbidimetric assay (LIA) and particle immunofiltration assay (PIFA) for heparin-induced thrombocytopenia (HIT) . Methods: Samples from 94 patients with suspected HIT from May 2016 to July 2018 in our hospital were prospectively analyzed by the two immunoassays. Their medical records and further follow-up data were also collected and analyzed by our hematologists to make the 4Ts scores and confirm the diagnosis of HIT, respectively. Performance characteristics of the two immunoassays were assessed, including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) . Their post-test probabilities (PTP) were also calculated based on the 4Ts score. Results: Among 94 cases, 15 (16.0%) had a positive HIT, including 6 of 37 (16.2%) with an intermediate, and 9 of 15 (60.0%) with a high 4Ts score. PIFA operating characteristics were: sensitivity 100.0% (15/15) , specificity 51.9% (41/80) , PPV 28.3% (15/53) , NPV 100.0% (41/41) . The positive PTP in intermediate and high 4Ts score group were 28.7% and 75.7%, respectively, while negative PTP were all 0. At manufacturers' cutoffs, LIA operating characteristics were: sensitivity 66.7% (10/15) , specificity 94.9% (75/79) , PPV 71.4% (10/14) and NPV 93.8% (75/80) . The positive and negative PTP in intermediate 4Ts score group were 71.8% and 6.3%, while 95.2% and 34.4% in high 4Ts score group, respectively. Receiver operating characteristic (ROC) analysis manifested that LIA was preferable than PIFA, and combining the 2 assays together was significantly better than single test. Conclusions: 4Ts score is still an important tool for the diagnosis of HIT. Combining clinical score with heparin/PF4 antibody assay can increase the accuracy of confirming or excluding HIT. Although PIFA is inferior to LIA in the diagnostic value, its user friendliness and 100% NPV have major advantages. Combining the 2 assays together can achieve a higher diagnostic value.

Hsp72 induction: a potential molecular mediator of the delay phenomenon.

The molecular basis of enhanced ischemic tissue survival in flaps preconditioned by surgical delay is poorly understood. Because elevated expression of so-called heat shock or stress proteins has been shown to protect tissues/organs against ischemic injury, the authors examined whether the levels of the most highly induced stress protein-hsp72-were elevated in delayed muscle flaps using a rat muscle flap model. Bilateral latissimus dorsi muscle flaps based on the thoracodorsal vessels were elevated in 16 male Sprague-Dawley rats. For each animal, one side was selected randomly to undergo preconditioning by surgical delay for a 7-day period prior to elevation. Delay was accomplished by preserving the thoracodorsal pedicle and a single large distal intercostal perforating vessel. After bilateral flap elevation, latissimus dorsi tissue was harvested from proximal, central, and distal flap segments 0, 1, 3, and 7 days postoperatively (N = 4 for each group), and was analyzed for the expression of hsp72 via Western blot analysis. At the time of harvest, flap viability was assessed by staining with nitroblue tetrazolium. Flap perfusion was measured prior to muscle elevation and harvest using laser Doppler flowmetry. The results demonstrate that delayed muscle flaps had significantly greater total perfusion (p < 0.05) and survival (p < 0.03) 1, 3, and 7 days after elevation compared with the acutely elevated control tissue. Western blot analysis revealed that tissues harvested from the delayed flaps expressed substantially higher levels of hsp72 compared with the acutely elevated control samples. Segmental analysis also revealed a proximal > middle > distal expression of hsp72 in the delayed flaps (p < 0.05). Flap preconditioning by surgical delay increases the expression of hsp72. Moreover, regional differences in hsp72 gene expression are associated with differences in perfusion and survival of delayed muscle flaps. These results indicate that hsp72 may play a substantial role in mediating the delay phenomenon.