Are central venous catheter tip cultures reliable after 6-day refrigeration?

Present guidelines recommend culturing only central venous catheter (CVC) tips from patients with suspected catheter-related bloodstream infection (CR-BSI). However, a high proportion of these suspicions are not confirmed. Moreover, CVC tip culture increases laboratory workload, and reports of colonization may be meaningless or misleading for the clinician. Our working hypothesis was that CVC tips should be refrigerated and cultured only in patients with positive blood cultures. We evaluated the effect of 6-day refrigeration of 215 CVC tips. We selected all the catheters with a significant count according to the Maki's roll-plate technique and randomly assigned them to 2 groups. In group A, the catheters were recultured after 24 h of refrigeration, and in group B, the catheters were recultured after 6 days more of refrigeration, so that the refrigeration time evaluated would be of 6 days. The yield of refrigerated CVC tips that grow significant colony counts of primary culture in group B was compared with the yield of refrigerated catheter tips in group A. The difference showed that 6-day refrigeration reduced the number of significant CVCs by 15.2%. Only 61 CVCs were obtained from patients with CR-BSI, and in most of them, blood cultures were already positive before CVC culture, so only 0.91% of the CR-BSI episodes would have been misdiagnosed as culture negative after refrigeration. Refrigeration of CVC tips sent for culture and culturing only those from patients with positive blood cultures reduce the workload in the microbiology laboratory without misdiagnosing CR-BSI.     

Effect of thermal treatments on arsenic species contents in food.

In arsenic-endemic and other areas, food is an important path of exposure to this contaminant. Food is generally consumed in processed form, after a preservation treatment or cooking, which may alter the concentrations and chemical forms of arsenic. This article summarizes and discusses the work so far published on the effect that thermal treatment used in the cooking or processing of food, including sterilization and preservation stages, has on total arsenic and arsenic species contents. It also reviews possible transformations in arsenic species. The studies included use model systems or food products of marine or vegetable origin. Processing may cause a considerable increase or decrease in the real arsenic intake from food. For example, traditional washing and soaking of Hizikia fusiforme seaweed, which has very high inorganic arsenic contents, may reduce the contents by up to 60%. On the other hand, all the arsenic present in cooking water may be retained during boiling of rice, increasing the contents of this metalloid to significant levels from a toxicological viewpoint. This calls for modifications in arsenic risk assessment, hitherto based on analysis of the raw product. It is necessary to consider the effect of processing on total arsenic and arsenical species in order to obtain a realistic view of the risk associated with intake in arsenic-endemic and other areas.     

凝血酶溶液冷藏保存对蚓激酶效价测定稳定性的影响

目的 初步考察分析凝血酶溶液冷藏保存对蚓激酶效价测定稳定性的影响。方法 采用冰箱冷藏方法 对凝血酶溶液进行保存,定期取出用于蚓激酶效价测定,统计分析其对蚓激酶效价测定的影响,并采用药物分析验证方法 对冷藏25d的凝血酶溶液用于蚓激酶效价测定进行相关方法 学验证。结果 凝血酶溶液冷藏0～25d,用于配制琼脂糖纤维蛋白平板,对测定蚓激酶效价无明显影响;凝血酶溶液冷藏至30d后,用于测定的蚓激酶效价偏低,且其标准曲线线性关系也较差,存在较明显影响;冷藏25d的凝血酶溶液用于效价测定方法 学验证,精密度、准确度和线性关系良好。结论 凝血酶溶液冷藏0～25d较为适宜,所配制琼脂糖纤维蛋白平板不影响蚓激酶效价的测定与判断。     

Impact of prolonged storage of clinical samples at 4 °C on the recovery of dermatophytes by culture or PCR analysis

Dermatophytes are common pathogens in superficial mycoses that are routinely identified by culture or PCR analysis of freshly collected skin, nail or hair specimens. Although clinical samples are normally processed without delay, practical or research issues may necessitate sample storage until later analysis. However, the influence of extended sample storage on the ability to recover fungi by culture vs. PCR analysis has not been specifically studied. Here, a total of 172 dermatological samples collected from 2013–2015 were examined before and after refrigerated storage at 4 °C for 10.2–32.3 (mean 25.6) months. By culture, 35% of the dermatophyte-containing fresh samples remained positive at re-examination. At species level, only 19% of initially Trichophyton rubrum-positive samples yielded a positive result after refrigeration, whereas few samples containing Trichophyton violaceum, Microsporum canis or Microsporum audouinii remained culture-positive. Using PCR, 76% of dermatophyte DNA-positive fresh samples were still positive at re-analysis. Notably, 92% of the samples targeted by the T. rubrum DNA primer remained positive after storage. Hence, PCR analysis is more favourable than cultivation with regard to the detectability of dermatophytes in long-term refrigerated clinical samples.     

草分枝杆菌注射液联合酞丁胺治疗甲周疣32例疗效观察

目的观察草分枝杆菌注射液联合酞丁胺搽剂治疗甲周疣的疗效。方法将64例甲周疣患者随机分成治疗组32例,予草分枝杆菌注射液肌肉注射和外搽酞丁胺搽剂;对照组32例,疣体采用液氮冷冻治疗,观察治疗时间均为2个月。结果治疗组痊愈率65.63%,有效率90.63%;对照组分别为21.88%,65.56%,两组临床疗效比较,差异有显著性(P均<0.05);随访3个月,两组复发率分别为9.25%,57.10%,差异也有显著性(P<0.05)。结论草分枝杆菌联合酞丁胺治疗甲周疣的疗效好、安全、无痛苦、无毒副作用,治疗后不遗留瘢痕,复发率低,易于接受,是治疗多发性甲周疣的有效方法。     

Short-term storage of tripronucleated human embryos

Purpose

To determine the survival and subsequent in vitro development of human cleavage stage embryos and hatched blastocysts following varying periods of short-term storage at 4 °C, using tripronucleated human embryos (TPN) as a model.

Methods

TPN cleavage embryos and hatched blastocysts short-term stored at 4 °C for 0 h (control), 24 h and 48 h. The main outcome measures were: survival rates (SR) and in vitro developmental ability (blastocyst rate and blastocyst-re-expansion rate) in each of the groups after storage.

Results

Cleavage-stage TPN survived at comparable rates to controls, regardless of storage time (average: 97.3 %). The in vitro development of cleavage-stage TPN stored for 24 h was comparable to that of controls (average 64.7 %), but was significantly impaired when storage lasted 48-h (20.8 %). After artificial shrinkage, SR was comparable in 24-h-stored and non-stored hatched blastocysts (85.7 %; p > 0.05), but was significantly impaired in the 48-h-stored group (20.0 %). Following 24-h storage, the re-expansion rate of hatched blastocysts was similar to that of controls (average: 57.1 %; p > 0.05), but was higher than that of the 48-h-stored group (15.0 %; p < 0.05).

Conclusions

TPN human cleavage embryos and blastocysts can be successfully stored short-term for up to 24 h at 4 °C without using cryoprotectants without any significant negative impact on survival or subsequent in vitro development.     

局部冷冻对血管及机体合成一氧化氮的影响

目的:本实验通过对在体家兔动脉及心脏局部冷冻,观察冷冻对血管合成一氧化氮功能的影响,以及机体对冷冻的全身性反应的有关征象。方法:以家兔作为实验对象,随机分成对照组和冷冻组,以Ignarro和Green法测定血管壁的NO_2~-含量,以Shechter法测定NO_2~-浓度,在实验中分别测定冷冻前后血管壁和血液中心NO_2~-浓度。结果:①主动脉及股动脉壁冷冻10秒复温后随时间的延长动脉管壁NO_2~-含量逐渐升高。②对主动脉管壁冷冻2分钟后可见主动脉管壁NO_2~-含量明显下降。③对主动脉壁冷冻10秒钟后,血液中的NO_2~-含量未见明显变化。①对心脏心外膜冷冻10秒钟后血液中NO_2~-含量未见明显变化。结论:血管壁的冷冻对血管合成一氧化氮(NO)的功能影响较大,当冷冻时间较短时,血管壁合成NO的量随时间延长而增多。但是,随首冷冻时间增加,血管壁合成NO的量减少,由此可造成不良的后果。     

Stability of vitamin C in fruit and vegetable homogenates stored at different temperatures

Vitamin C loss was compared in homogenized raw broccoli, potatoes, spinach, strawberries, oranges, and tomatoes; baked potatoes; steamed broccoli and spinach; and pasteurized orange juice after storage under residual nitrogen under refrigeration, and frozen at conventional (−10 to −20 °C) and ultra-low (<−55 °C) temperatures for 1, 3, and 7 days. Additional foods (cantaloupe, green sweet peppers, collard greens, clementines) were monitored for 3–4 years at <−55 °C. Total ascorbic acid was quantified using high-performance liquid chromatography and detailed quality control measures. No decrease occurred in any of the foods after 7 days at <−55 °C. Under refrigeration the largest decreases were in raw spinach and broccoli, averaging (mg/100 g) 9.5 (29%) and 33.1 (29%), respectively, after 1 day and 31.0 and 77.0 after 7 days (94% and 68%, respectively). With conventional freezing, vitamin C was stable for 7 days in most of the products studied; minor losses occurred in raw spinach and broccoli after 1 day but were substantial after 3 days, 6.9 mg/100 g (23%) and 17.0 mg/100 g (15%), respectively; and 7 days (13.1 and 32.0 mg/100 g). For homogenates stored long-term at <−55 °C, vitamin C loss occurred in only cantaloupe, collard greens, and one sample of raw potatoes, all before 50 weeks.     

Progressive gas formation in a deceased person during mortuary storage demonstrated on computed tomography

We report the case of an 82-year-old woman with a past history of diabetes mellitus who died following blunt head injury sustained in a fall resulting in an acute subdural hematoma. Serial postmortem CT scans of the chest and abdomen performed over a 3-day period demonstrated progressive intra-hepatic and intra-cardiac gas formation whilst the deceased was stored in a standard mortuary refrigerator at a nominated temperature of 4°C. Measured mortuary refrigerator temperatures over a 7 day period showed statistically significant day to day variability in temperatures above 4°C as well as variations in temperature depending on location within the refrigerator space. In the absence of other known factors associated with such gas formation, putrefaction seems the likely cause despite a lack of obvious external features. This phenomenon must therefore be taken into account when interpreting the presence of visceral gas on postmortem CT and relating such gas to the cause of death.