Environmental exposure to lead and cadmium and hearing loss in Chinese adults: A case-control study.

Hearing loss is the second most common nonfatal problem affecting the Chinese population. Historical studies have suggested an association between exposure to heavy metals, such as cadmium and lead, and hearing loss. Few studies have investigated this relationship in the general population in China. We conducted a case-control study with 1008 pairs of participants from a cross-sectional epidemiological survey conducted in Zhejiang Province. A self-designed questionnaire was adopted to collect information on demographics, chronic diseases, lifestyles and environmental noise. Pure-tone averages of hearing thresholds at frequencies of 0.5, 1, 2, and 4 kHz were computed. Blood lead and cadmium levels were analyzed with an atomic absorption spectrometer. After adjusting for all other potential confounding factors, compared with the lowest blood cadmium quartile (0.00-0.53 µg/L), blood cadmium quartile 2 (0.54-0.92 µg/L), quartile 3 (0.93-1.62 µg/L) and quartile 4 (1.63-57.81 µg/L) exhibited significantly elevated risks for hearing loss, with odds ratios of 1.932 (95% CI: 1.356-2.751), 2.036 (95% CI: 1.423-2.914) and 1.495 (95% CI: 1.048-2.133), respectively (P-trend<0.001). However, an association of lead with hearing loss was not found. Young age (less than 60 years), male sex and current smoking were associated with increased blood cadmium concentration. Additionally, a positive association between blood cadmium and lead concentrations was found. Therefore, we conclude that exposure to environmental cadmium may be a risk factor for hearing loss among the general population in China.

Temperature effects on enzyme activity of chicken liver esterase used in calorimetric biosensor.

The temperature effects on enzyme activity at the conditions with and without inhibition, operation, and storage were investigated for free esterase and immobilized chicken liver esterase with three methods (adsorption, adsorption-microcapsule, and adsorption-crosslinking) used in a calorimetric biosensor. The results indicated that the temperature had significant effects on the enzyme activity by means of catalytic reaction, irreversible denaturation, mass transfer, and structure deformation of resin. Among all the esterase, the adsorption-crosslinking immobilized esterase had the best performances of enzyme activity retention ratio (EARR), above 96% in operation and 90% in storage on condition of maintaining its response to dichlorvos.

[Nipple-areolar reconstruction with the modified arrow flap].

OBJECTIVE: To introduce the clinical experience of nipple-areolar reconstruction with the modified arrow flap. METHODS: The arrow flaps were modified for nipple-areolar reconstruction in 12 cases. Among them, 2 cases were treated with combined thin split-thickness skin graft; 4 cases with autologous rib implant and tattoo; 6 cases with tattoo. RESULTS: All the reconstructed nipples were survived. The reconstructed nipples lost projection 1 month after operation in 2 cases. The other 10 cases retained 50% of the nipple projection 3 months after operation. The results were maintained with satisfactory symmetry during the follow-up period of 6 months to one year. CONCLUSIONS: The modified flap is easily performed with reasonable design and no need of donor site. The nipple projection can be maintained with good long-term effect.

[The best concentration ratio of propofol controlled-infusion combined with sevoflurane in anesthesia for patients undergoing laparoscopy].

OBJECTIVE: To investigate the best concentration ratio of propofol controlled-infusion combined with sevoflurane in anesthesia for patients undergoing laparoscopy. METHODS: One hundred patients undergoing cholecystectomy under laparoscopy were randomly divided into 5 equal groups treated with propofol controlled plasma at the concentrations of 1, 2, 3, 4, and 5 microg/ml respectively (Group 1-5). Bispectral index (BIS) was maintained at a range of 50 +/- 5 by adjusting sevoflurane inhalation. The end-tidal concentration of sevoflurane (ETsevo), systolic pressure, diastolic pressure, recovery time, awareness, and post-operative nausea and vomiting (PONV) within 24 h after operation were recorded. The best concentration ratio of propofol controlled-infusion combined with sevoflurane with the definition as the highest ETsevo without PONV decrease along with the increase of propofol concentration. RESULTS: ETsevo was negatively correlated with and propofol concentration. There were nit significant differences in the systolic pressure, diastolic pressure, and recovery time among different groups. No incidence of intra-operative awareness was found. The PONV rates of Group 1 and 2 were both 60%, significantly higher than those of the other 3 groups (all P < 0.05) without significant differences in PONV rate among Group 3 - 5. The best concentration ratio of propofol controlled-infusion combined with sevoflurane was propofol controlled-infusion at the concentration of 1 microg/ml with ETsevo at the concentration as 1 minimal alveolar concentration (MAC). CONCLUSION: Propofol controlled-infusion at the concentration of 1 microg/ml with ETsevo at the concentration as 1 MAC is the best concentration ratio with low PONV rate and a possibility to prevent intra-operative awareness.

[Breast reconstruction with a combined skin flap of DIEP and TRAM].

OBJECTIVE: To evaluate breast reconstruction with a combined skin flap of the deep inferior epigastric perforator (DIEP) and the transverse rectus abdominis musculocutaneous (TRAM). METHODS: The DIEP and TRAM united flap was elevated with the vessel pedicle of the deep inferior epigastric perforator on the affected side and the rectus abdominis muscle pedicle on the intact side. The reconstructive breast was shaped after the deep inferior epigastric vessels were anastomosed to the internal mammary vessels or the thoracodorsal vessels ipsilaterally. RESULTS: We have used the DIEP and TRAM united flaps for breast reconstruction in 17 cases. All of the flaps survived, and the reconstructed breasts were well-shaped with the follow-up of 6-18 months. CONCLUSIONS: The DIEP and TRAM united flap possesses of advantages such as rich blood supply, abundant tissue volume and easy shaping. It is especially applicable to the cases who have large chest defect and need large volume tissue.

A thermal biosensor based on enzyme reaction.

Application of the thermal biosensor as analytical tool is promising due to advantages as universal, simplicity and quick response. A novel thermal biosensor based on enzyme reaction has been developed. This biosensor is a flow injection analysis system and consists of two channels with enzyme reaction column and reference column. The reference column, which is set for eliminating the unspecific heat, is inactived on special enzyme reaction of the ingredient to be detected. The special enzyme reaction takes places in the enzyme reaction column at a constant temperature realizing by a thermoelectric thermostat. Thermal sensor based on the thermoelectric module containing 127 serial BiTe-thermocouples is used to monitor the temperature difference between two streams from the enzyme reaction column and the reference column. The analytical example for dichlorvos shows that this biosensor can be used as analytical tool in medicine and biology.