Simultaneous analysis of skin response to the different L.E.T. regions of a 55 MeV helium ion beam

Summary Rat tail epidermis was used to analyze the in vivo response of a biological system to heavy particle irradiation. The conical configuration of the rat tail gives rise to a variable energy degradation of the beam thus yielding information on the damage elicited by 2 different L.E.T. regions of the helium beam at different sites on the same sample. Cytochrome oxidase activity and epidermal thickness were used to analyze the metabolic and structural radioinduced response. Quantitative evaluation of radiation damage revealed marked variations within a few micrometers of tissue.     

In vivo response to the different LET regions of a 55 MeV helium ion beam

We evaluated the in vivo response to heavy particle irradiation in rat tail epidermis using silver-stained nucleolar organizer regions (AgNOR) as the end-point. The energy degradation of the beam across the circular section of the tail allowed us to study the damage elicited by two different LET regions of a helium beam, i.e. non-Bragg peak (NBP) and Bragg peak (BP), at different sites on the same sample. The tails were locally irradiated with a helium ion beam at different fluences. AgNOR exhibited marked variations between tissue areas only a few micrometers apart within each tail exposed to a given beam fluence. An analysis of the AgNOR variations in NBP and BP areas of tails exposed to different beam fluences revealed a dose-dependent effect. The AgNOR provide quantitative evidence of differential damage in neighboring tissue areas exposed to different LET regions of a helium-ion beam.     

Exposure to non-ionizing electromagnetic fields emitted from mobile phones induced DNA damage in human ear canal hair follicle cells

The aim of this study was to investigate effect of radiofrequency radiation (RFR) emitted from mobile phones on DNA damage in follicle cells of hair in the ear canal. The study was carried out on 56 men (age range: 30–60 years old)in four treatment groups with n = 14 in each group. The groups were defined as follows: people who did not use a mobile phone (Control), people use mobile phones for 0–30 min/day (second group), people use mobile phones for 30–60 min/day (third group) and people use mobile phones for more than 60 min/day (fourth group). Ear canal hair follicle cells taken from the subjects were analyzed by the Comet Assay to determine DNA damages. The Comet Assay parameters measured were head length, tail length, comet length, percentage of head DNA, tail DNA percentage, tail moment, and Olive tail moment. Results of the study showed that DNA damage indicators were higher in the RFR exposure groups than in the control subjects. In addition, DNA damage increased with the daily duration of exposure. In conclusion, RFR emitted from mobile phones has a potential to produce DNA damage in follicle cells of hair in the ear canal. Therefore, mobile phone users have to pay more attention when using wireless phones.     

Effects of helium and other inert gases on Echinosphaerium nucleofilium (protozoa, heliozoa).

The effects of helium, nitrogen, argon and krypton on Echinosphaerium nucleofilum (Heliozoa) have been studied at partial pressures of 10-130 atm. Additional experiments have been carried out with hydrostatic pressure alone. Helium causes shortening of the axopods over the whole range of pressures, and damage to the cell body at pressures of 60-90 atm, both with a maximum at 80 atm. These effects cannot be explained in terms of hydrostatic pressure alone; a 'pressure reversal' effect may be operating, causing the peak at 80 atm. Nitrogen also causes both cell damage and axopod shortening, the severity increasing with increasing pressure. Argon and krypton cause cell damage but no shortening. The order of potency for cell damage is krypton greater than argon greater than nitrogen greater than helium. It is suggested that there may be tuo sites of action, possibly the microtubules (for axopod shortening) and the cell membrane (for cell damage). In appropriate mixtures of helium and argon, both the cell damage usually caused by argon, and the axopod shortening usually caused by helium, are prevented. Possible mechanisms include the effects of hydrostatic pressure on gas solubility coefficients, reversal of the effects of the gases by the increase in total pressure, and competition for sites of action.     

A note on the structure of tail hairs from a pygmy hippopotamus (Choeropsis liberiensis)

The pygmy hippopotamus (Choeropsis liberiensis), like the Nile hippopotamus (Hippopotamus amphibius), defecates by backing into vertical objects while making a series of rapid, propellerlike tail movements that spread a mixture of urine and feces in a wide swath. Split hairs from the distal ventral surface of the pygmy hippopotamus tail were studied with the scanning electron microscope to determine whether the splitting was a normal character of the hair or was due to damage. The results suggest that splitting is a normal feature of the hair that may facilitate the dispersal of urine and feces.     

R.b.e. and o.e.r. of extended-Bragg-peak helium ions: survival and development of rat embryos.

Rats were exposed under aerobic or hypoxic conditions to 200-1200 rads of 60Co gamma-rays or extended-Bragg-peak helium ions on the eighth day of gestation. Uterine contents were examined on the twentieth day of gestation. At the 50 per cent embryonic survival level, helium ion r.b.e. was 1(.0) (aerobic) and 1(.2) (hypoxic). Maximum attainable gamma-ray and helium-ion o.e.r.s. were 2(.2) and 1(.7) respectively, indicating an oxygen-effect gain (o.e.g.) of 1(.2). At the 10 per cent survival level helium ion r.b.e. was 1(.1) (aerobic) and 1(.4) (hypoxic). Gamma-ray and helium-ion 0.e.r.s. were 2(.0) and 1(.5) respectively, indicating a helium ion o.e.g. of 1(.3). These data demonstrate that the small fraction of high-LET radiation present in this helium ion beam has a neglible effect on the aerobic r.b.e., but lowers the effective o.e.r. of the beam approximately 25 per cent relative to that of gamma-rays. Helium ions were significantly more effective than gamma-rays in killing embryos under hypoxic conditions, in producing congenital abnormalities under aerobic conditions, and in stunting foetal growth under both conditions.     

The role of the C-terminal region of rat brain natriuretic peptide in receptor selectivity.

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) have different C-terminal tail structures compared with the rather conservative ring structures which consist of 17 amino acid residues. To examine the different effects of the tail structures of ANP and BNP on their interaction with receptors, we synthesized several peptide analogs and measured their biological actions in three different assay systems. Deletion of the C-terminal tail from rat BNP did not effect the vasorelaxation activity against rat aorta, but it promoted cGMP production in cultured rat aortic smooth muscle cells (RASMC). Deletion of the C-terminal tail from rat ANP diminished both vasorelaxant and cGMP producing activities. In a binding competition assay with RASMC and [125I]rat ANP-(1-28), the competition activities of both ANP and BNP were greatly reduced by C-terminal deletion. In addition, we obtained agonists with novel receptor selectivity.     

Kinky coat, a new autosomal recessive mutation in the musk shrew, Suncus murinus.

A kinky-coat mutant was discovered at the fifth generation of the BAN strain originating from wild musk shrews (Suncus murinus) in Bangladesh. Mating experiments indicated that the kinky-coat character is controlled by a single autosomal recessive gene designated kc (kinky coat), which is not allelic to the gene ch (curly hair) previously reported in the Tr strain derived from wild musk shrews on Taramajima Island, Japan. Because the kc/kc homozygotes were fully fertile and viable, the kc gene should be useful as a genetic marker in linkage studies. In external appearance, homozygotes were characterized by curly vibrissae, somewhat unkept coat hair, and wavy long hair on the tail. Both the length and width of coat hair did not differ significantly between homozygous and normal shrews. Light microscopic observations showed that shafts of the kc coat hair are wavy and often have small swellings with disorganization of the medullary structure. Scanning electron microscopic examinations further revealed that the shafts of the vibrissae, coat hair, and tail hair have abnormalities such as longitudinal fissures, twists, and hollows. It is clear that these modifications caused waviness or curling of the shafts of the three kinds of hairs observed.     

伤害性刺激和非伤害性刺激对大鼠丘脑后核神经元电活动的影响

用微电极细胞外记录的方法,观察内脏痛、躯体痛和触觉刺激对大鼠丘脑后核(PO)中770个神经元电活动的影响,其中305(38.3％)个对伤害性刺激起反应,103(13.4％)个对触觉刺激起反应。对伤害性刺激反应的神经元中多数对躯体痛和内脏痛刺激均起反应且反应形式相同,少数反应不同或相反,对触觉刺激反应的神经元中多数也对两种伤害性刺激均起反应,只对触觉刺激反应的神经元很少。     

He–Ne laser (632.8 nm) pre‐irradiation gives protection against DNA damage induced by a near‐infrared trapping beam

We report the results of a study carried out to investigate the effect of He–Ne laser (632.8 nm) pre‐irradiation on DNA damage induced by continuous wave 1064 nm trapping beam exposure in MCF‐7 cells. A significant decrease in % tail DNA (p < 0.05) was observed in MCF‐7 cells pre‐exposed to He–Ne laser beam. The dependence of the induced protection against 1064 nm trapping beam irradiation induced DNA damage on the time interval between the two irradiations as well as the He–Ne laser pre‐irradiation parameters is presented. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Detection of mutagens in the urine of rats following topical application of hair dyes.

Mutagens were detected in the urine of rats following topical application of two commercial oxidative-type hair dye preparations. The test system used was induction of back mutation with the bacterial tester strain TA1538, a histidine-dependent mutant of Salmonella typhimurium. Various quantities of dye were applied to the shortened hair on the backs of the test animals. The dye was allowed to remain on the hair for 20 min after application and was then removed by shampooing and thorough rinsing. Maximal levels of mutagenic activity occurred with urine collected during first 24 h following dye application, and a dose--response was observed when increasing volumes of mutagenic urine were tested. Mutagens were detected in rat urine after intraperitoneal injection, and also after topical application of 4-nitro-o-phenylenediamine, one of the constituents of the hair-dye preparations.     

The mechanical and biochemical properties of tail tendon in a rat model of obesity: Effect of moderate exercise and prebiotic fibre supplementation

The worldwide trajectory of increasing obesity rates is a major health problem precipitating a rise in the prevalence of a variety of co-morbidities and chronic diseases. Tendinopathy, in weight and non-weight bearing tendons, in individuals with overweight or obesity has been linked to metabolic dysfunction resulting from obesity. Exercise and dietary fibre supplementation (DFS) are common countermeasures to combat obesity and therefore it seems reasonable to assume that they might protect tendons from structural and mechanical damage in a diet-induced obesity (DIO) model. The purpose of this study was to determine the effects of a DIO, DIO combined with moderate exercise, DIO combined with DFS (prebiotic oligofructose), and DIO combined with moderate exercise and DFS on the mechanical and biochemical properties of the rat tail tendon. Twenty-four male Sprague-Dawley rats, fed a high-fat/high-sucrose diet were randomized into a sedentary, a moderate exercise, a DFS, or a moderate exercise combined with DFS group for 12 weeks. Additionally, six lean age-matched animals were included as a sedentary control group. DIO in combination with exercise alone and with exercise and DFS reduced the Young’s Modulus but not the collagen content of the rat tail tendons compared to lean control animals. However, no differences in the mechanical and biochemical properties of the rat tail tendon were detected between the DIO and the lean control group, suggesting that DIO by itself did not impact the tail tendon. It seems that longer DIO exposure periods may be needed to develop overt differences in our DIO model.     

改良的大鼠模拟失重模型制备方法*

目的: 介绍一种改良的尾部悬吊使后肢去负荷的制备大鼠模拟失重模型的方法。方法: 90只成年雄性SD大鼠随机分为对照组,经典尾吊组和改良尾吊组(每组30只)。经典尾吊组利用医用胶带和纱布制作大鼠尾套后悬吊大鼠尾部。改良尾吊组在上述操作基础之上,在尾套内增加聚乙烯发泡棉隔层,以缓冲纱布对尾部的挤压,保证远端血液循环。对照组尾部不做特殊处理。尾吊4周后观察尾部损伤和尾套脱落等并发症,测量大鼠体质量及右侧比目鱼肌湿重。结果: 与对照组相比,经典尾吊组的比目鱼肌湿重/体质量比值显著减少,但体质量无显著差异,大鼠尾部远端出现缺血坏死损伤的发生率为40.0%,尾套脱落的发生率为26.7%,模型成功率为33.3%;与经典尾吊组相比,改良尾吊组的尾部损伤程度明显降低,远端缺血坏死率为13.3%, 尾套脱落率为3.3%,模型成功率为83.3% (P均＜0.05)。结论: 采用改良尾吊法建立大鼠模拟失重模型能够显著减少鼠尾坏死和尾套脱落发生率,简单易行,提高了模型制备的成功率。     

氟对大鼠肝组织细胞凋亡与DNA损伤的影响

目的研究大鼠染氟后肝组织细胞凋亡及DNA损伤情况。方法 SD大鼠随机分为对照组、低氟组、中氟组、高氟组,每组12只,分别饮用含氟化钠为0、50、100、200 mg/L的去离子水,均饲标准营养大鼠饲料,染氟120 d。肉眼观察牙齿的变化,采用氟离子选择电极法测定大鼠尿氟,HE染色观察组织病理学变化,彗星实验检测细胞DNA损伤,流式细胞术检测肝脏组织细胞凋亡率。结果低氟组、中氟组、高氟组大鼠尿氟分别为（23.52±2.91）、（30.16±4.78）、（61.23±3.98）mg/L,均显著高于对照组（0.07±0.02）mg/L,差异有统计学意义（P〈0.01）。不同剂量染氟大鼠肝组织细胞呈现不同程度肿胀,肝组织内出现多种灶状病变。各染氟组大鼠肝细胞拖尾率及拖尾长度与相应的对照组相比,差异均有统计学意义,并且肝细胞拖尾率及拖尾长度随染氟剂量的加大而增大。不同剂量染氟组细胞凋亡率与对照组相比,均明显增高,而且高、中氟组肝细胞凋亡率显著高于低氟组（P〈0.01）。结论氟化物可导致大鼠肝细胞DNA损伤,诱导细胞凋亡,一定浓度的氟化物诱导大鼠肝细胞凋亡与DNA损伤之间存在着相关性。     

D-半乳糖致衰老模型大鼠体征和骨髓DNA含量的改变与中药干预作用

目的观察D-半乳糖致衰老模型大鼠的一般症状、皮肤状况、饮食嗜好及骨髓细胞DNA含量的变化,并探讨中药抗衰老的作用及其机制。方法大鼠每日一次皮下注射D-半乳糖,连续7周,建立衰老大鼠模型,观察衰老大鼠的一般症状和体重变化,测定其皮肤含水量、糖水消耗量和骨髓细胞DNA含量,并用抗衰老片和首乌延寿片进行干预,观察中药对衰老模型大鼠的干预作用。结果大鼠皮下注射D-半乳糖后,逐渐出现体重增长缓慢、行动迟缓、精神不振、嗜睡、被毛卷曲枯黄、光泽欠佳、尾部出现色素斑点等衰老症状,并在造模第5周出现体重下降,造模7周后,衰老大鼠的皮肤含水量和糖水消耗量明显减少（P〈0.05）,骨髓细胞的DNA含量亦明显减少（P〈0.01）;给予抗衰老片和首乌延寿片后,均可不同程度地延缓衰老症状,缓解体重的下降,显著提高皮肤的含水量和糖水消耗量（P〈0.01）,同时,明显提高骨髓细胞DNA含量（P〈0.05）。结论D-半乳糖致衰老大鼠模型的衰老体征明显,机体抗DNA损伤的能力下降,而抗衰老片和首乌延寿片等中药可明显改善衰老模型大鼠的衰老症状,其作用机制可能与提高机体修复DNA损伤的能力有关。     

Expression of Growth Factors and Their Receptors in the Postnatal Rat Cochlea

RT-PCR was used to assay for growth factors and receptors from seven different protein families in cochlea tissues of the juvenile rat. There was a broad representation of the growth factor families in all the cochlea tissues examined, though the organ of Corti and stria vascularis expressed a greater variety than the spiral ganglion. This broad expression suggests that a variety of known growth factors play significant roles in the development, maintenance, and repair of the inner ear. The results of this survey serve as a basis for the design of future in vitro experiments that will address the ability of growth factors to protect hair cells from damage and to evoke a repair-regeneration response by injured hair cells.     

In vivo and in vitro aging of collagen examined using an isometric melting technique.

1. In vivo and in vitro aging of tendon from rat tail, kangaroo tail and human wrist tendon was examined by the technique of isometric melting, in physiological saline. 2. For all these collagens, two mechanisms of structure stabilisation can be distinguished in the melting curves. One of these involves co-valent cross-linking as judged by its increasing stability to heat and acid pH, while the second appears to involve only secondary interactions. 3. The time rate of the first process is slow in vivo; rat tendon up to 2 years does not show it, but it is present in 6-year-old human tendon. However, its in vitro rate is markedly dependent upon the free oxygen content of the physiological saline. At an oxygen concentration of 300 nmol/ml, the in vitro aging rate is about 30 times the in vivo rate for rat tail tendon, and about 20 times for both kangaroo tail tendon and human wrist tendon. At a concentration of 60 nmol/ml (which is about the same as normal arteriovenous blood difference) in vitro aging proceeds close to the in vivo rate.     

Germ cell and dose-dependent DNA damage measured by the comet assay in murine spermatozoaa after testicular X-irradiation

The single-cell gel electrophoresis (Comet) assay has been widely used to measure DNA damage in human sperm in a variety of physiological and pathological conditions. We investigated the effects of in vivo radiation, a known genotoxin, on spermatogenic cells of the mouse testis and examined sperm collected from the vas deferens using the neutral Comet assay. Irradiation of differentiating spermatogonia with 0.25-4 Gy X-rays produced a dose-related increase in DNA damage in sperm collected 45 days later. Increases were found when measuring Comet tail length and percentage of tail DNA, but the greatest changes were in tail moment (a product of tail length and tail DNA). Spermatids, spermatocytes, differentiating spermatogonia, and stem cell spermatogonia were also irradiated in vivo with 4 Gy X-rays. DNA damage was indirectly deduced to occur at all stages. The maximum increase was seen in differentiating spermatogonia. DNA damaged cells were, surprisingly, still detected 120 days after stem cell spermatogonia had been irradiated. The distribution of DNA damage among individual sperm cells after irradiation was heterogeneous. This was seen most clearly when changes in the Comet tail length were measured when there were discrete undamaged and damaged populations. After increasing doses of irradiation, an increasing proportion of cells were found in the damaged population. Because a proportion of undamaged sperm cells remains after all but the highest dose, the possibility of normal fertility remains. However, fertilization with a spermatozoa carrying high amounts of DNA damage could lead to effects as diverse as embryonic death and cancer susceptibility in the offspring.     

新生小鼠不同部位皮肤毛囊早期发育差异的比较

目的观察出生后小鼠不同部位皮肤毛囊早期发育生长差异及细胞色素C的表达分布。方法对新生1~9日龄的KM小鼠背部、尾部和触须部皮肤取材,进行HE染色,用二步法免疫组织化学对组织进行细胞色素C进行表达分布检测。结果新生小鼠不同部位皮肤毛囊发育差异很大,这种差异不仅体现在形态差异上,而发育时间的差异也十分明显。小鼠出生后背部皮肤和尾部皮肤的毛囊发育都经过了一个非线性的发育和生长期,过了非线性的发育和生长期才开始快速生长,相比较尾部发育略迟于背部。触须部毛囊发育特征和背部尾部差异很大,一出生便可看到较成熟的触毛,没有经过稳定期便开始发育。结论通过形态学比较,结合CytC表达分布水平,发现新生小鼠不同部位皮肤毛囊早期发育存在形态和时间上的差异。