Site-Specific Structural Variations Accompanying Tubular Assembly of the HIV-1 Capsid Protein

The 231-residue capsid (CA) protein of human immunodeficiency virus type 1 (HIV-1) spontaneously self-assembles into tubes with a hexagonal lattice that is believed to mimic the surface lattice of conical capsid cores within intact virions. We report the results of solid-state nuclear magnetic resonance (NMR) measurements on HIV-1 CA tubes that provide new information regarding changes in molecular structure that accompany CA self-assembly, local dynamics within CA tubes, and possible mechanisms for the generation of lattice curvature. This information is contained in site-specific assignments of signals in two- and three-dimensional solid-state NMR spectra, conformation-dependent ¹⁵N and ¹³C NMR chemical shifts, detection of highly dynamic residues under solution NMR conditions, measurements of local variations in transverse spin relaxation rates of amide ¹H nuclei, and quantitative measurements of site-specific ¹⁵N–¹⁵N dipole–dipole couplings. Our data show that most of the CA sequence is conformationally ordered and relatively rigid in tubular assemblies and that structures of the N-terminal domain (NTD) and the C-terminal domain (CTD) observed in solution are largely retained. However, specific segments, including the N-terminal β-hairpin, the cyclophilin A binding loop, the inter-domain linker, segments involved in intermolecular NTD–CTD interactions, and the C-terminal tail, have substantial static or dynamical disorder in tubular assemblies. Other segments, including the 3₁₀-helical segment in CTD, undergo clear conformational changes. Structural variations associated with curvature of the CA lattice appear to be localized in the inter-domain linker and intermolecular NTD–CTD interface, while structural variations within NTD hexamers, around local 3-fold symmetry axes, and in CTD–CTD dimerization interfaces are less significant.     

Further studies of human whole-body radiofrequency absorption rates

Further studies of human whole-body radiofrequency (RF) absorption rates were carried out using a TEM-cell exposure system. Experiments were done at one frequency near the grounded resonance frequency (approximately 40 MHz), and at several below-resonance frequencies. Absorption rates are small for the K and H orientations of the body, even when grounded. For the body trunk in an E orientation, the absorption rate of a sitting person is about half of the rate for the same person standing with arms at the sides; the latter in turn is about half the rate for the same subject standing with arms over the head. Two-body interactions cause no increase in absorption rates for grounded people. They do, however, increase the absorption rates for subjects in an E orientation in free space; the largest interaction occurs when one subject is lambda/2 behind the other (as seen by the incident wave). When these results are applied to practical occupational exposure situations, the whole-body specific absorption rate does not exceed the ANSI limit of 0.4 W/kg for exposures permitted by the ANSI standard (C95.1-1982) at frequencies from 7 to 40 MHz.     

Biological effects of high-frequency electromagnetic fields on Salmonella typhimurium and Drosophila melanogaster

Salmonella typhimurium and Drosophila melanogaster were exposed to continuous wave (CW) 2.45-GHz electromagnetic radiation, pulsed 3.10-GHz electromagnetic radiation, CW 27.12-MHz magnetic fields, or CW 27.12-MHz electric fields (only Drosophila). The temperatures of the treated sample and the nonexposed control sample were kept constant. The temperature difference between exposed and control samples was less than +/- 0.3 degrees C. Ames' assays were made on bacteria that had been exposed to microwaves (SAR 60-130 W/kg) or RF fields (SAR up to 20 W/kg) when growing exponentially in nutrient broth. Survival and number of induced revertants to histidine prototrophy were determined by common plating techniques on rich and minimal agar plates. The Drosophila test consisted of a sensitive somatic system where the mutagenicity was measured by means of mutations in a gene-controlling eye pigmentation. In none of these test systems did microwave or radiofrequency fields induce an elevated mutation frequency. However, a significantly higher concentration of cells was found in the bacterial cultures exposed to the 27-MHz magnetic field or 2.45-GHz CW and 3.10-GHz pulsed microwave radiation.     

Experimental study and mechanism analysis on bioeffects by nanosecond electromagnetic pulses

The athermal bioeffects caused by nanosecond electromagnetic pulses with body cells was studied by using a broad band transverse EM-wave cell (BTEM CELL). The experimental system and preliminary mechanism analysis were presented.     

A circular waveguide irradiation system for nonhuman primates: design and dosimetry

A 275-MHz exposure system, consisting of a circular waveguide irradiator and a transparent plastic animal cage, has been developed to accommodate rhesus monkeys weighing up to 15 kg. The vertically oriented waveguide is composed primarily of stainless steel and is fitted with an inner cage fabricated from a tubular section of acrylic plastic. Circularly polarized electromagnetic energy at 275 MHz, either pulsed or continuous wave (CW), can be propagated from the removable top section of the waveguide. The cage is designed to function as the monkey's permanent home. It is fitted with a lever-actuated behavioral performance device on which the monkey responds according to a predetermined schedule to obtain a daily food ration. The system can be adapted to provide for the collection of metabolic and physiologic data as well. Dosimetric measurements were conducted with six rhesus monkeys weighing 3.0-7.2 kg and with a 4-kg model. The dosimetric results show that about one-third of the net incident energy is absorbed by a subject in this system at a normalized specific absorption rate (SAR) of 0.33 (W/kg)/(mW/cm2).     

Effect of microwaves (2450-MHz) on the immune system in mice: studies of nucleic acid and protein synthesis

CBA/J adult male mice were given single or triple exposures to 2450-mHz microwaves in an environmentally controlled wave guide facility. The average absorbed dose rate for a single exposure varied from 12 to 15 mW/g. Sham-exposed mice served as controls. Lymphoid cells were collected and tested for metabolic activity on days 3, 6, and 9 following a single exposure, and on days 9, 12, and 16 following triple exposures on days 0, 3, and 6. Cells were cultured in vitro for four hours to seven days before their metabolic rates were assayed. Under these conditions, microwaves failed to produce any detectable change in deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein synthesis, as measured by the incorporation of methyl(3H)-thymidine (3H-TDR) (DNA substrate), 3H-uridine (3H-UR) (RNA substrate), and 3H-leucine (protein substrate) by spleen, bone marrow, and peripheral blood lymphocytes (PBL) in vitro. These data suggest that microwave-induced increases in the frequency of complement-receptor (CR)- or surface-immunoglobulin (sIg)-bearing cells were not associated with a concomitant increase in cell proliferation and/or protein synthesis, and favor the concept that microwaves under these conditions stimulate already existing B-cell precursors for maturation.     

超声引导下腔内射频消融联合点式剥脱治疗下肢静脉曲张的临床效果观察

目的:探讨超声引导下腔内射频消融(radiofrequency endovenous obliteration,RFO)联合点式剥脱治疗下肢静脉曲张的临床疗效及安全性。方法:选取2017年10月至2018年10月哈尔滨医科大学附属第一医院收治的下肢静脉曲张患者共320例(320条肢体),将其随机分为观察组200例和对照组120例。观察组200例(200条肢体)采用超声引导下腔内射频消融联合点式剥脱进行治疗,对照组120例(120条肢体)采用传统大隐静脉高位结扎剥脱、曲张静脉点式剥脱治疗。比较两组患者平均住院时间、术后并发症的发生情况及术后1年下肢静脉的彩超随访情况。结果:观察组患者平均住院时间较对照组显著缩短,术后皮肤瘀斑、皮下血肿、隐神经损伤、切口感染的发生率显著低于对照组(P0.05),两组患者术后1年复查,其复发率及大隐静脉主干闭塞情况比较差异没有统计学意义(P0.05)。结论:与传统大隐静脉高位结扎剥脱、曲张静脉点式剥脱治疗相比,超声引导下腔内射频消融联合点式剥脱治疗下肢静脉曲张的疗效及安全性均更高,有利于患者术后康复。     

Association Between Mobile Phone Radiation Exposure and the Secretion of Melatonin and Cortisol,Two Markers of the Circadian System: A Review

The extremely important use of mobile phones in the world, at all ages of life, including children and adolescents, leads to significant exposure of these populations to electromagnetic waves of radiofrequency. The question, therefore, arises as to whether exposure to these radiofrequencies (RFs) could lead to deleterious effects on the body's biological systems and health. In the current article, we review the effects, in laboratory animals and humans, of exposure to RF on two hormones considered as endocrine markers: melatonin, a neurohormone produced by the pineal gland and cortisol, a glucocorticosteroid synthesized by the adrenal glands. These two hormones are also considered as markers of the circadian system. The literature search was performed using PubMed, Medline, Web of Sciences (ISI Web of Knowledge), Google Scholar, and EMF Portal. From this review on RF effects on cortisol and melatonin, it appears that scientific papers in the literature are conflicting, showing effects, no effects, or inconclusive data. This implies the need for additional research on higher numbers of subjects and with protocols perfectly controlled with follow‐up studies to better determine whether the chronic effect of RF on the biological functioning and health of users exists (or not). Bioelectromagnetics. 2021;42:5–17. © 2020 Bioelectromagnetics Society     

化疗联合冷循环射频消融术治疗原发性肝癌的效果分析

目的：探讨化疗联合冷循环射频消融术治疗原发性肝癌的疗效及安全性。方法：108例原发性肝癌患者随机分为两组,均给予灌注化疗,每4周进行一次灌注化疗,对照组（n=54）进行3次,治疗组（n=54）只进行一次。治疗组给予冷循环射频消融术。评价生活质量Kamofsky评分,治疗前后检查患者的血、尿、便常规,肝肾功能（包括天冬氨酸转氨酶、丙氨酸转氨酶（AVr）、白蛋白（ALB）、总胆红素、肌酐及尿素氮等指标）,甲胎蛋白（AFP）,T细胞亚群和加强肝脏CT扫描。随访1年,经CT确定肝癌复发。结果：治疗组Kamofsky评分有效率为59．26％,对照组Kamofsky评分有效率为37．03％,两组Kamofsky评分有效率相比较,差异有统计学意义（P〈0．05）。两组治疗后症状变化相比较,除腹胀外其余各项指标差异均有统计学意义（P〈O．05）。治疗后两组相比较,ALT和AFP差异有统计学意义（P〈0．05）。治疗后两组T细胞亚群变化相比较,治疗组各项指标均变化显著（P〈0．05）。治疗后随访一年,治疗组复发率为22．22％;对照组复发率为53．70％。两组治疗一年后复发率相比较,差异有统计学意义（P〈0．05）。结论：化疗结合冷循环射频消融术治疗原发性肝癌疗效肯定,并发症及副作用小,复发率低。     

Complications of nonionizing radiofrequency on divided attention

Exposure to electromagnetic fields is considered as a potential hazard for biological systems. The objective of our investigation is the study of probable consequences of radiofrequency electromagnetic fields from Wi-Fi router devices on the short-term memory, and attention's levels. A population consisting of 312 female college students (14 to 17 years old) was elected by cluster random sampling. Teenagers were divided into two groups of control group (Wi-Fi nonusers; n = 138), and experiment group (Wi-Fi users; n = 174). Both groups have been examined using short-term memory tests; selective attention, and also divided attention tests. According to the results, there was no significant difference between using Wi-Fi router devices on levels of selective attentions and short-term memory of the sample students with the control group. However, analyses revealed that there is a significant correlation between the use of Wi-Fi routers and declining levels of divided attentions. Our investigation has demonstrated the adverse consequences of 2.4-2.48 GHz radiofrequency electromagnetic fields of Wi-Fi router devices on divided attention levels of female university students that should be mentioned as a technological risk factor and taken into account by healthcare organizations.