The A.M.A. Session

The use of liquid nitrogen for the removal of warts has advantages over electrocautery in certain circumstances. Although the incidence of recurrences after liquid nitrogen is higher than after cautery, it causes considerably less scarring. It is most useful in dealing with peri-ungual and multiple warts.The technique is simple and a supply of liquid nitrogen can be kept on hand in the office at relatively low cost.     

PULMONARY HYALINE MEMBRANE DISEASE—A Panel Discussion: Internist's Point of View

Seventy-six digital and periungual warts in 40 patients were treated topically with cantharidin, a potent blistering agent. The material, dissolved in equal parts of acetone and collodion, was applied directly to the warts. Occlusion facilitated blistering. No pretreatment was required. The warts were re-treated at weekly intervals until clinically cured.Fifty-six per cent of digital warts and 33 per cent of periungual warts cleared after a single application of cantharidin. Few required more than three treatments. Observation was continued for more than six months in more than half of the cases. Cure was lasting in about 70 per cent of the cases in which the long term result was known.Cantharidin ranks with liquid nitrogen in effectiveness, but it is painless to apply and does not cause scarring. For these reasons it is especially useful in children.The main disadvantage is pain and tenderness at the treated site for two to four days in some patients. This can be avoided by careful application of the drug. Occasionally new warts appear at the edge of the cantharidin blister. They are best treated by curettage and desiccation.     

LIQUID NITROGEN IN THE TREATMENT OF SKIN DISEASES

Liquid nitrogen is a satisfactory freezing agent in the treatment of such skin diseases as warts, keratoses, superficial hemangiomas, leukoplakia, keloids, superficial scarring and dermatitis venenata. It is available and easily applied. Its use is described and the results of treatment in 154 cases of warts are presented.     

Nitrogen-Fixing Bacteria from Warty Lenticellate Bark of a Mangrove Tree, Bruguiera gymnorrhiza (L.) Lamk

Detached warty lenticellate bark of a mangrove tree species, Bruguiera gymnorrhiza (L.) Lamk. from Iriomote Island, Okinawa, a subtropical region of Japan, showed development of acetylene reduction activity when incubated in a mineral nutrient solution lacking nitrogen under an atmosphere consisting of 5% O(2), 90% N(2), and 5% C(2)H(2). The bacteria responsible for nitrogen fixation were isolated from the bark, and their capacity for acetylene reduction and the incorporation of N(2) into the bacterial cells was confirmed. Four representative strains of the isolates were subjected to taxonomic classification. Two strains were similar to Enterobacter cloacae, and another resembled Enterobacter aerogenes. The characteristics of the fourth strain were similar to those of Klebsiella planticola (Bagley et al., Curr. Microbiol. 6:105-109, 1981). The results of this investigation suggest that the acetylene reduction activity of lenticellate warts of mangrove trunk bark is due to the presence in the warts of nitrogen-fixing bacteria belonging to the family Enterobacteriaceae.     

Cryopreservation of basidiomycete strains using perlite.

A new alternative method using perlite as a particulate solid carrier in the growth medium with a cryoprotectant was successfully tested for cryopreservation of several basidiomycete species from different genera (Armillaria, Pleurotus, Pluteus, Polyporus) which failed to survive or retain their properties in cryopreservation procedures routinely used in our laboratory. Frozen basidiomycete strains were kept in cryovials submerged in liquid nitrogen and were either immediately after the freezing process or after a 6-month storage thawed and checked for viability, purity and changes in growth, morphology and biochemical characteristics. All cultures survived the cryopreservation procedure and no negative effects of cryopreservation by this method have been observed after 6 months of storage in liquid nitrogen.     

液氮冷冻联合兰科肤宁治疗孕妇尖锐湿疣的临床效果评价

目的:评价液氮冷冻联合兰科肤宁治疗孕妇尖锐湿疣的临床疗效与安全性。方法:回顾性分析我院收治的46例患有尖锐湿疣的孕妇,平均年龄为27岁,妊娠平均18周。每例患者的病灶数为5~18个。应用液氮枪喷涂于皮损,液氮枪距皮损2-3 cm,喷雾时间60秒,重复操作直至喷嘴霜化。将蓝科肤宁喷涂于单层纱布,敷于皮损部位20分钟,每天2-3次,共1周。分别于治疗后1月、3月观察皮损愈合情况,评价治疗效果。结果:治疗5天后,皮损均治愈,所有患者除有轻度至中度疼痛外,无其他不适。治疗后1个月,满意度94%;治疗后3个月,满意度为87%。无色素脱失或瘢痕形成,无任何严重不良事件。每位孕妇均分娩出一个健康的婴儿,无分娩相关并发症。治疗后1个月,只有1例病人复发,复发率为2.2%。治疗后3月,5例复发,复发率为10.9%。结论:液氮冷冻联合蓝科肤宁治疗孕妇尖锐湿疣的近期疗效较好,安全性较高。     

The vestured pits of Eucalyptus regnans F. Muell.: a study using scanning electron microscopy

Scanning electron microscopy has been used to examine the surface architecture, before and after various chemical treatments, of the pits in the walls of vessels, vasicentric and fibre tracheids, and parenchyma cells, which together make up the wood of Eucalyptus regnans. The treatments included water at 150°C under pressure, hydrofluoric acid, delignifying agents and potassium permanganate. All bordered pits were vestured; half-bordered pits were vestured, partially vestured or non-vestured. No distinction could be made between warts and vestures on morphological or chemical grounds. An hypothesis is advanced which relates vesture formation to prolongation of the activity of the protoplast in pits as the cells die. Vestures, on the basis of this hypothesis, could be regarded as enlarged or conglomerate warts.     

Cryopreservation of somatic embryos and embryonic axes of Camellia japonica L.

Summary Cryopreservation in liquid nitrogen was attempted with both somatic embryos and zygotic embryonic axes of the ornamental Camellia japonica L. Several protective measures were applied to somatic embryos (desiccation, chemical protectors, hardening by culture at low temperatures, encapsulation in alginate beads), but none allowed somatic embryos cultures to survive after 24 h in liquid nitrogen. Embryonic axes, however, were easily cryopreserved by means of the simplest technique: desiccation in a laminar flow hood and direct immersion in liquid nitrogen. Although the causes of the difference in cryopreservability between the two types of material are not known, one might be the difference between their degrees of differentiation and water content.Abbreviations ANOVA analysis of variance - BA N6-benzyladenine - DMSO dimethyl sulfoxide - IBA indole-3-butyric acid - LN liquid nitrogen - MS Murashige and Skoog mineral solution - fwt fresh weight - LSD Least Significant Difference     

The maintenance of challenge strains used in the potency test for canine leptospira vaccines.

The challenge test for leptospira vaccines required by most licensing authorities is difficult to standardise and unreliable. One of the main contributory factors to this, is the difficulty in maintaining the virulence of the challenge strain. This paper describes work carried out to assess the practicality of storing challenge strains of Leptospira canicola and Leptospira icterohaemorrhagiae in liquid nitrogen. The effects of different concentrations of glycerol and dimethyl sulphoxide on the recovery of virulent and avirulent strains of Leptospira canicola and Leptospira icterohaemorrhagiae were investigated. Concentrations of cryopreservant above 5% increased the time taken for the leptospires to grow after recovery from vials stored in liquid nitrogen. In addition, the virulence of five challenge strains were shown to be little affected after 18 passages in vitro.     

Molecular cloning and characterization of the DNAs of human papillomaviruses 19, 20, and 25 from a patient with epidermodysplasia verruciformis.

Five human papillomavirus (HPV) DNAs from lesions of an epidermodysplasia verruciformis patient were cloned in lambda L 47: DNA of HPV 5, which predominated in the carcinoma; DNA of a variant type of HPV 8, which was not detected in the carcinoma DNA by Southern blot hybridization but only by cloning; and DNAs of three papillomaviruses that were isolated from warts. Southern blot and liquid phase DNA-DNA hybridization under stringent conditions showed that the three viruses from warts were new types, which we named HPVs 19, 20, and 25. These viruses cross-hybridized between 3 and 29% among themselves and with HPVs 5 and 8. After physical mapping with several restriction enzymes, the colinear genomes were aligned with HPV 8 DNA to define early and late regions. HPVs 8, 19, and 25 shared homology in different parts of their genomes.     

Long-Term Storage of Infective Microsporidian Spores in Liquid Nitrogen

Thirty-one species of microsporidia, isolated from insects and stored in liquid nitrogen for up to 25 yr, were infectious when removed from liquid nitrogen. The natural hosts of all of these microsporidia were terrestrial insects, representing six different insect orders: Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, and Orthoptera. All microsporidia from terrestrial insects that were tested survived storage in liquid nitrogen, while Nosema algerae , a microsporidium from aquatic mosquito hosts did not survive freezing in liquid nitrogen. A Nosema species from the alfalfa weevil, Hypera postica , lost some infectivity in a water storage medium after 25 yr in liquid nitrogen. Liquid nitrogen storage of microsporidian spores in 50% and 100% glycerol media reduced loss of infectivity and is recommended for extended storage of microsporidia from terrestrial insect hosts.     

Schistosoma mansoni: cryopreservation of schistosomules.

Conditions were established for recovery of active schistosomules of Schistosoma mansoni after cryopreservation and storage in liquid nitrogen (?196 C). Schistosomules prepared from cercariae by a shear pressure technique were subjected to a two-step cooling process consisting of a slow cooling rate to an intermediate temperature, followed by rapid quenching of the sample in liquid nitrogen. Overall averages of 39 and 44% of the schistosomules, with a maximum of 88%, were recovered retaining normal activity with cooling rates of 0.4 C/min to ?32 C or 0.8 C/min to ?35 C, respectively. Methanol at 17.5% in Earle's lactalbumin hydrolysate was the freezing medium. As compared with 24 hr storage in liquid nitrogen, no loss in schistosomule motility was observed after 1 month. Following cryopreservation, attenuated schistosomules derived from ⁶⁰Co-irradiated cercariae (50 kR) exhibited structure and activity equivalent to that of unattenuated schistosomules. Infectivity for mice of unattenuated schistosomules derived from ⁶⁰Co-irradiated cercariae (50 Krad) exhibited structure and activity of unfrozen schistosomules ranged from 0.4 to 15.2%.     

Cryotherapy with liquid nitrogen versus topical salicylic acid application for cutaneous warts in primary care: randomized controlled trial

Background

Cryotherapy is widely used for the treatment of cutaneous warts in primary care. However, evidence favours salicylic acid application. We compared the effectiveness of these treatments as well as a wait-and-see approach.

Methods

Consecutive patients with new cutaneous warts were recruited in 30 primary care practices in the Netherlands between May 1, 2006, and Jan. 26, 2007. We randomly allocated eligible patients to one of three groups: cryotherapy with liquid nitrogen every two weeks, self-application of salicylic acid daily or a wait-and-see approach. The primary outcome was the proportion of participants whose warts were all cured at 13 weeks. Analysis was on an intention-to-treat basis. Secondary outcomes included treatment adherence, side effects and treatment satisfaction. Research nurses assessed outcomes during home visits at 4, 13 and 26 weeks.

Results

Of the 250 participants (age 4 to 79 years), 240 were included in the analysis at 13 weeks (loss to follow-up 4%). Cure rates were 39% (95% confidence interval [CI] 29%–51%) in the cryotherapy group, 24% (95% CI 16%–35%) in the salicylic acid group and 16% (95% CI 9.5%–25%) in the wait-and-see group. Differences in effectiveness were most pronounced among participants with common warts (n = 116): cure rates were 49% (95% CI 34%–64%) in the cryotherapy group, 15% (95% CI 7%–30%) in the salicylic acid group and 8% (95% CI 3%–21%) in the wait-and-see group. Cure rates among the participants with plantar warts (n = 124) did not differ significantly between treatment groups.

Interpretation

For common warts, cryotherapy was the most effective therapy in primary care. For plantar warts, we found no clinically relevant difference in effectiveness between cryotherapy, topical application of salicylic acid or a wait-and-see approach after 13 weeks. (ClinicalTrial.gov registration no. ISRCTN42730629)Cutaneous warts are common.^1–3 Up to one-third of primary school children have warts, of which two-thirds resolve within two years.^4,5 Because warts frequently result in discomfort,⁶ 2% of the general population and 6% of school-aged children each year present with warts to their family physician.^7,8 The usual treatment is cryotherapy with liquid nitrogen or, less frequently, topical application of salicylic acid.^9–12 Some physicians choose a wait-and-see approach because of the benign natural course of warts and the risk of side effects of treatment.^10,11A recent Cochrane review on treatments of cutaneous warts concluded that available studies were small, poorly designed or limited to dermatology outpatients.^10,11 Evidence on cryotherapy was contradictory,^13–18 whereas the evidence on salicylic acid was more convincing.^19–23 However, studies that compared cryotherapy and salicylic acid directly showed no differences in effectiveness.^24,25 The Cochrane review called for high-quality trials in primary care to compare the effects of cryotherapy, salicylic acid and placebo.We conducted a three-arm randomized controlled trial to compare the effectiveness of cryotherapy with liquid nitrogen, topical application of salicylic acid and a wait-and-see approach for the treatment of common and plantar warts in primary care.     

Factors in the cryopreservation of bone marrow cells from children with acute lymphocytic leukemia.

Bone marrow cells from 42 children with acute lymphocytic leukemia in remission and 19 normal adults were preserved in liquid nitrogen for periods of up to 50 weeks. Many factors in the process of cryopreservation were investigated in an attempt to optimize the recovery of the bone marrow colony forming cells. The effect of cryopreservation on the cells which produce colony stimulating activity also was investigated. With optimization of this technique, it was observed that approximately 100% of the bone marrow nucleated cells were recovered and approximately 50% of the total colony forming cells were viable after 50 weeks in liquid nitrogen.     

Warts and wart virus antibodies in patients with systemic lupus erythematosus.

Warts were found in 25 out of 56 patients with definite or probable systemic lupus erythematosus (SLE) but in only 19 out of 160 control patients. Warts were particularly prevalent in elderly patients with SLE. The corticosteroid and antimalarial drugs used to treat SLE did not influence the frequency of warts. Wart-virus antibodies were found significantly less often in patients with SLE than in controls: antibodies were detected in 23 out of 51 patients and in 40 out of 54 controls. Ihe findings suggest that some deficiency in the immune mechanisms of patients with SLE predisposes them to develop warts. There was an inverse correlation among the patients with SLE between the occurrence of warts and rheumatoid factor activity. This suggests that rheumatoid factor may interfere with resistance to warts.     

Liquid Nitrogen Freezing in Microbiological Assay Systems: I. Preservation of Lactobacillus leichmannii for Direct Use in the Vitamin B12 Assay

Suspensions of Lactobacillus leichmannii were stored in liquid nitrogen and were used as direct inocula in vitamin B₁₂ assays. Complete recovery of viable cells was obtained when the suspensions in basal B₁₂ medium were rapidly frozen by direct immersion into liquid nitrogen and rapidly thawed by agitating the suspensions in a water bath at 40 C. Greater than 90% destruction occurred when the suspensions were in saline. However, both suspensions were usable in the B₁₂ assay system. Assay results on a number of test materials indicated good correlation between freshly prepared suspensions and frozen suspensions in basal medium stored 3 months. Suspensions in saline stored for 1 year in liquid nitrogen showed no detectable difference from the first day after freezing. Suspensions frozen slowly at the rate of 1 degree per min from 4 to -40 C and subsequently immersed in liquid nitrogen had a longer lag period of growth and were not usable in the 18-hr assay incubation system. A major advantage of a stored inoculum for direct use in a microbiological assay is the reduced day-to-day variation in the inoculum.     

Liquid nitrogen storage of yeast cultures. II. Stability of characteristics of stored strains

Nineteen strains of yeasts possessing different characteristics were stored in liquid nitrogen and after 5 years phenotypic characters were evaluated and compared with equivalent strains preserved under paraffin oil. All qualitative characters tested remained stable, and quantitative characters varied only within the range of natural variability.     

植物挥发性物质提取的一种简易方法--液氮冷凝法

介绍了植物挥发物提取的一种简易方法——液氮冷凝法。利用液氮的制冷原理对植物挥发性物质进行提取收集,当携带植物挥发性物质的纯净空气带动供试植物组织的挥发性物质通过一置有U形玻璃管的液氮罐时,由于液氮的低温作用,挥发性物质在U形管内壁上遇冷凝结。该提取装置简单,由硅胶柱、活性碳柱、流量计、锥形瓶、U形管、液罐及各种连接管构成,容易组装。利用该装置提取的挥发性物质可以用于生测,去除水分后还可用于电生理以及挥发性物质化学组成分析等。     

Liquid nitrogen vapour freezing of mouse embryos

Mouse morulae were frozen rapidly to -196 degrees C in the presence of glycerol by a two-step procedure; the embryos were transferred directly from -7 degrees C after seeding into liquid nitrogen vapour at -170 to -180 degrees C and then into liquid nitrogen 10-15 min later. Suitable conditions for the survival of embryos frozen with liquid nitrogen vapour were found to be: 2 M-glycerol, 2 M-propylene glycol, 2 M-ethylene glycol; 5-30 min equilibration time at 0 degrees C; 3-60 min holding time in liquid nitrogen vapour; dilution of glycerol with sucrose out of the frozen-thawed embryos; morula and early blastocyst stage embryos. Relatively high survival rates (69-74%) were obtained after rapid freezing by liquid nitrogen vapour. Morulae frozen in this fashion, cultured and transferred to recipients developed into normal young.     

用SDS-PAGE和Vorum银染法比较真菌菌丝体破壁效果

目的:研究不同处理方法对丝状真菌Pythium sp.GY1938菌丝体破壁效果的差异。方法:采用7种方法对真菌菌丝体进行破壁处理,将制备的胞内可溶蛋白质样品通过SDS-PAGE和Vorum法银染处理,比较不同破壁方法处理后蛋白质释放效果的优劣。结果:方法VI(石英砂、液氮、研磨)的破壁效果最好,蛋白质的分离效率和提取质量最高。结论:方法VI适合于丝状真菌Pythium sp.GY1938蛋白组学研究中目的蛋白的提取。