Far-field microwave dosimetry in a rhesus monkey model

Dosimetric measurements were made in a muscle-equivalent model of an adult rhesus monkey subjected to far-field irradiation at 1.29 GHz. Profiles of microwave-induced heating in the model were obtained at eight locations, and a gradient-layer whole-body calorimeter was used to measure total absorbed energy. Average specific absorption rate (SAR) was calculated both from the calorimeter experiments and from the local temperature measurements. Thermographic imaging techniques were used to qualitatively show the microwave-induced surface heating patterns. For this model the calculated average SAR was 0.155 (W/kg)/(mW/cm²) which, at 1.29 GHs, makes the absorption cross section 84% of the geometric shadow cross section. The SAR is about three times that predicted for a prolate spheroidal model of similar mass. A disproportionally high absorption occured in the legs of the model positioned parallel to the E-polarization because of what is believed to be partial-body resonance.     

Specific absorption rate (SAR) in models of the human head exposed to hand-held UHF portable radios

Specific absorption rate (SAR) was measured in models of the human head exposed to hand-held portable radios ("transceivers") transmitting at frequencies in the 800-MHz band. An isotropic implantable electric-field probe was used to measure internal fields induced in the head models, and SARs were determined by calculation. As well as determining representative values and distributions for SARs under various conditions, it was shown that antenna type and orientation with respect to the head are important factors affecting energy absorption.     

Metabolic and vasomotor responses of rhesus monkeys exposed to 225-MHz radiofrequency energy

A previous study showed a substantial increase in the colonic temperature of rhesus monkeys (Macaca mulatta) exposed to radiofrequency (RF) fields at a frequency near whole-body resonance and specific absorption rates (SAR) of 2-3 W/kg. The present experiments were conducted to determine the metabolic and vasomotor responses during exposures to similar RF fields. We exposed five adult male rhesus monkeys to 225 MHz radiation (E orientation) in an anechoic chamber. Oxygen consumption and carbon dioxide production were measured before, during, and after RF exposure. Colonic, tail and leg skin temperatures were continuously monitored with RF-nonperturbing probes. The monkeys were irradiated at two carefully-controlled ambient temperatures, either cool (20 degrees C) or thermoneutral (26 degrees C). Power densities ranged from 0 (sham) to 10.0 mW/cm2 with an average whole-body SAR of 0.285 (W/kg)/(mW/cm2). We used two experimental protocols, each of which began with a 120-min pre-exposure equilibration period. One protocol involved repetitive 10-min RF exposures at successively higher power densities with a recovery period between exposures. In the second protocol, a 120-min RF exposure permitted the measurement of steady-state thermoregulatory responses. Metabolic and vasomotor adjustments in the rhesus monkey exposed to 225 MHz occurred during brief or sustained exposures at SARs at or above 1.4 W/kg. The SAR required to produce a given response varied with ambient temperature. Metabolic and vasomotor responses were coordinated effectively to produce a stable deep body temperature. The results show that the thermoregulatory response of the rhesus monkey to an RF exposure at a resonant frequency limits storage of heat in the body. However, substantial increases in colonic temperature were not prevented by such responses, even in a cool environment.     

A description of the upper thoracic autonomic nervous system in the rhesus monkey (Macaca mulatta)

The purpose of this study was to describe the autonomic innervation of the carotid sinus and heart in the rhesus monkey. Nine male rhesus monkeys (Macaca mulatta) and one male crab-eating macaque (M. fascicularis) were carefully dissected from the origin of the vagus nerves and superior cervical ganglia to the level of the fourth thoracic ganglion. The specimens were either freshly killed or obtained no later than 24 hours post mortem. The macaque monkeys were found to possess an innervation pattern that displayed features common to dog (connections between the vagus nerves and middle cervical ganglia), baboon (distinct cervical sympathetic and cervical vagal nerve trunks), and man (nerves projecting from the middle cervical and stellate ganglia to the heart). Distinct inferior cervical and first thoracic ganglia were never seen, but rather, large and well defined stellate ganglia were found. The macaque innervation pattern, when considered as a whole, most closely resembled the baboon.     

Operant behavior and colonic temperature of Macaca mulatta exposed to radio frequency fields at and above resonant frequencies

Five food-deprived rhesus monkeys were exposed to 225-MHz continuous-wave, and 1.3-GHz, and 5.8-GHz pulsed radiation to determine the minimal power densities affecting performance. The monkeys were trained to press a lever (observing-response) thereby producing signals that indicated availability of food. In the presence of the aperiodically appearing food signals, a detection response on a different lever was reinforced by a food pellet. Continuous, stable responding during 60-min sessions developed and was followed by repeated exposures to radiofrequency radiation. The subjects, restrained in a Styrofoam chair, were exposed to free-field radiation while performing the task. Colonic temperature was simultaneously obtained. Observing-response performance was impaired at increasingly higher power densities as frequency increased from the near-resonance 225 MHz to the above-resonance 5.8 GHz. The threshold power density of disrupted response rate at 225 MHz was 8.1 mW/cm²; at 1.3 GHz it was 57 mW/cm², and at 5.8 GHz it was 140 mW/cm². These power densities were associated with reliable increases in colonic temperatures above sham-exposure levels. The mean increase was typically in the range of 1°C, and response-rate changes were not observed in the absence of concomitant temperature increases. In these experiments increase of colonic temperature was a much better predictor of behavioral disruption than was either the power density of the incident field or estimates of whole-body-averaged rates of energy absorption.     

Effect of sugar type on the survival of frozen-thawed rhesus monkey (Macaca mulatta) sperm

Sperm-freezing extenders supplemented with sugar or a combination of different sugars are widely used for the cryopreservation of nonhuman primate spermatozoa. Understanding which sugar or combination of sugars offers the highest level of cryoprotection would be beneficial for the development of sperm-freezing extenders. In the present study we aimed to investigate the effect of glucose, lactose, and raffinose separately or in combination on the cryosurvival of rhesus monkey spermatozoa. Toward that end, we prepared eight extenders by adding various types of sugars to a basic medium (BM): G-BM (0.3 M glucose), L-BM (0.3 M lactose), R-BM (0.3 M raffinose), LG-BM (0.15 M lactose+0.15 M glucose), RG-BM (0.15 M raffinose+0.15 M glucose), LR-BM (0.15 M lactose+0.15 M raffinose), and LRG-BM (0.1 M lactose+0.1 M raffinsoe+0.1 M glucose). A saline control (0.157 M sodium chloride) was also used. The results showed no significant difference in post-thaw motility when spermatozoa were frozen with G-BM, L-BM, LG-BM, RG-BM, and LRG-BM, but the post-thaw motility was significantly lower when it was frozen with R-BM, LR-BM, and the saline control. The highest plasma membrane integrity was achieved when spermatozoa were frozen with G-BM, L-BM, LG-BM, RG-BM, and LRG-BM, and the highest acrosome integrity was achieved with G-BM, L-BM, LG-BM, RG-BM, LRG-BM, and the saline control. The results indicate that the various sugars offered different protective effects. For the cryopreservation of rhesus monkey spermatozoa, glucose (monosaccharide) and lactose (disaccharide) were shown to be more suitable than raffinose (trisaccharide) for preserving spermatozoal motility, plasma membrane, and acrosome. Specifically, raffinose was detrimental to sperm acrosome integrity.     

Placental transfer of synthetic and endogenous estrogen conjugates in the rhesus monkey (Macaca mulatta)

The placental transfer of conjugated and nonconjugated estrogens was compared in the pregnant rhesus monkey. Placement of catheters in the maternal and fetal circulation allowed for the sampling of blood after the administration of radiolabeled naturally occurring and synthetic estrogens to mother or fetus. In all cases, nonconjugated-estrogen placental transfer was greater than conjugated-estrogen transfer. Comparison of the conjugated estrogens suggested that diethylstilbestrol-monoglucuronide (DESG) was transferred less efficiently than the estrone-sulfate (E, S). High-performance liquid chromatog-raphy (HPLC) of selected plasma samples revealed that 50–90% of the E, S observed in the maternal circulation was cleaved after fetal administration. In contrast, HPLC of maternal or fetal plasma samples after DESG administration revealed only intact DESG. These results emphasize differences in the placental transfer of the synthetic and naturally occurring estrogen hormones.     

Effect of nonionizing radiation on the purkinje cells of the uvula in squirrel monkey cerebellum

Pregnant squirrel monkeys were exposed to 2450-MHz (CW) microwaves at an equivalent power density of 10 mW/cm² (SAR 3.4 mW/g) for three hours daily in a cavity-cage module. The exposure began when pregnancy was determined by a hormonal method, and continued through the offspring's first 9.5 months. After irradiation, the brains of the offspring were fixed with formaldehyde, and the inferior vermis of each cerebella was removed and processed for histologic observations. Purkinje cell density in the uvula was determined in sagittal serial sections. There was no significant difference between control and experimental animals in the number of Purkinje cells per mm of Purkinje cell line (linear density), as well as in the density of Purkinje cells in the Purkinje cell layer.     

Laboratory assessment of temperament and environmental enrichment in rhesus monkey infants (Macaca mulatta)

This study investigated the combined effects of early temperamental characteristics and environmental enrichment on a variety of developmental measures in nursery-reared rhesus monkey infants. Twenty-three infants, reared in either standard laboratory cages or enriched environments, were tested during the 1st month of life for interactive, motor, and temperamental capabilities and characteristics. At 8 months of age, all subjects were assessed on a second series of tests designed to measure their problem-solving skills, motor capabilities, and temperamental responses under challenge. Results indicated that enrichment was associated with higher scores on subsequent problem-solving and motor tests. However, such effects were found to combine with early temperament ratings. Specifically, individuals performing best on the 8-month tests had not only been reared in enriched environments, but also had been rated low on fearfulness during the early assessment. In addition, individuals scoring poorest had been rated as fearful initially in addition to being reared without enrichment. Results indicated that while high ratings on early laboratory assessments of fearfulness may be predictive of poorer problem-solving performance under challenging conditions, these adverse effects may be partially attenuated by environmental enrichment.     

米非司酮对恒河猴母胎界面细胞凋亡和凋亡分子p53表达的影响

胎盘形成过程中发生活跃的细胞增殖、迁移和凋亡等活动。p53蛋白是参与调节细胞周期和凋亡过程的原癌基因。本实验用原位末端标记、蛋白印迹和免疫组织化学方法研究正常和米非司酮(RU486)处理后恒河猴母胎界面绒毛和蜕膜组织细胞凋亡及p53蛋白表达。在正常妊娠的恒河猴母胎界面,凋亡信号主要集中在合体滋养层和细胞柱内的一些滋养层细胞;p53蛋白主要定位于细胞滋养层。在母体蜕膜中,也在部分基质细胞中检测到细胞凋亡和p53蛋白表达。经过RU486处理2d后,胎盘绒毛和母体蜕膜中凋亡细胞数都显著增加,绒毛中增加的凋亡信号集中于细胞滋养层。同时,RU486处理也导致绒毛细胞滋养层和蜕膜基质细胞中p53表达明显增加。以上结果提示,在正常妊娠中,生理性的细胞凋亡和p53表达可能是控制细胞滋养层细胞增殖、保持胎盘组织动态平衡的一个重要机制;RU486终止早孕的可能途径之一是促进母胎界面细胞凋亡,推测p53参与这一过程。     

Specific absorption rate in models of man and monkey at 225 and 2,000 MHz

Full-size models of a man and a rhesus monkey were exposed to radiofrequency (RF) radiation at 225 MHz. The model of man was also exposed to 2,000 MHz. Specific absorption rates (SARs) were measured in partial-body sections, such as the arms, legs, etc., using gradient-layer calorimeters. Also, front-surface thermographic images were obtained to qualitatively show the heating patterns. For all of the configurations used, the SAR in the limbs was much higher than in the torso. Agreement (whole-body SARs) with spheroidal models was better for both models at 225 MHz than at 2,000 MHz. These results indicate that in the frequency range two orders of magnitude above whole-body resonance, SAR in the limbs significantly contributes to the whole-body average SAR.     

Quantitation of serum immunoglobulins G, M, and A in the rhesus monkey (M. mulatta) using human monospecific antisera in the enzyme-linked immunosorbent assay: developmental aspects

Using human monospecific antisera, several parameters have been optimized for the micro-ELISA "sandwich" technique used in the quantitative measurement of total serum IgG, IgM and IgA levels in rhesus monkeys. Representation of the optical density as a four-parameter logistic function provided excellent fits of the data over a wide choice of dilutions of human antisera used for coating the ELISA plates and for the peroxidase-conjugated antisera used in the system. The micro-ELISA "sandwich" technique was shown to be specific, reliable, sensitive, and economical for use in the routine measurement of total serum IgG, IgM and IgA levels in the rhesus monkey.     

The available time window for embryo transfer in the rhesus monkey (Macaca mulatta)

Much effort has been focused on improving assisted reproductive technology procedures in humans and nonhuman primates (NHPs). However, the pregnancy rate after embryo transfer (ET) has not been satisfactory, indicating that some barriers still need to be overcome in this important procedure. One of the key factors is embryo–uterine synchronicity, which is little known in NHPs. The objective of this study was to investigate the available ET time window in rhesus monkey (Macaca mulatta). Eighty-two adult female rhesus monkeys were superovulated with recombinant human FSH. Ovarian phases were identified according to estrogen (E2) and progesterone (P4) levels as well as ovarian examination by ultrasonography and laparoscopy. A total of 259 embryos were transferred by the laparoscopic approach into the oviducts of 63 adult female monkeys. Ovarian phases were divided into late follicular and early luteal phases. Similar pregnancy rates (30–36.4%) were obtained from recipients receiving ET either in their late follicular or early luteal phases, regardless of embryo developmental stages. This study indicates that the available time window for ET in rhesus monkeys is from the late follicular to early luteal phases.     

Expression of prostasin and protease nexin-1 in rhesus monkey (Macaca mulatta) endometrium and placenta during early pregnancy.

Serine proteases have been documented to play key roles in uterine matrix turnover and trophoblastic invasion during implantation. Roles of prostasin serine protease in these processes, however, are currently unclear. The present study was first conducted to investigate the colocalization of prostasin and its cognate serpin, protease nexin-1 (PN-1), in rhesus monkey endometrium and placenta on days 12, 18, and 26 of pregnancy by using in situ hybridization (ISH) and immunohistochemistry. With ISH, expression of prostasin mRNA was intensely localized in the glandular epithelium on days 12 and 18 and in the placental villi, trophoblastic column, trophoblastic shell, and fetal-maternal border on days 18 and 26. With the progress of pregnancy, expression level in the glandular epithelium was significantly decreased, and the accumulation in the placental compartments was further increased. In addition, the stroma and arterioles exhibited modest levels of prostasin signals. However, expression level of PN-1 in these compartments on adjacent sections in the three stages of early pregnancy was weak or below the level of detection. Prostasin protein expression in the endometrium was found to be consistent with the distribution patterns revealed in the ISH experiments. It may be suggested from these results that prostasin is involved in endometrial epithelial morphology establishment, tissue remodeling, and trophoblastic invasion during early pregnancy. The cognate serpin PN-1 was not coordinately expressed along with prostasin, creating a tissue environment favorable for proteolytic activities of prostasin during early pregnancy events.     

Changes in hematology, biochemical values, and restraint ECG of rhesus monkeys (Macaca mulatta) following 6-month laboratory acclimation

The aim of this study was to determine if 6-month acclimation would enable accurate evaluation of hematological, biochemical data, and ECG recorded under restraint for conscious rhesus monkeys of both sexes. Periodic evaluation of these parameters was made during the 6-month period of acclimation. The platelet count, alkaline phosphatase, glucose, and sodium levels significantly decreased, whereas creatinine increased, compared with pre-acclimation values. The heart rate was significantly reduced compared with pre-acclimation values. QT-RR relation followed the square root regression function, which means modification of Bazett's QTc formula can be applied even if the ECG is recorded under restraint. In conclusion, 6-month acclimation was effective for stabilizing the blood data and for allowing accurate evaluation of the ECG even under restraint. Current results show that an acclimation period at least 3 months may be necessary prior to using rhesus monkeys for chronic studies.     

Effect of nonionizing radiation on the purkinje cells of the rat cerebellum

In one experiment, Sprague Dawley rats (16–21 days of gestation) and their offspring were exposed to 100-MHz (CW) electromagnetic radiation at 46 mW/cm² (SAR 2.77 mW/g) for 4 h/day for 97 days. In another experiment, the pregnant rats were irradiated daily from 17 to 21 days of gestation with 2450-MHz (CW) microwaves at 10 mW/cm² (SAR 2 mW/g) for 21 h/day. In a third experiment, 6-day-old rat pups were irradiated 7 h/day for five days with 2450-MHz radiation at 10 mW/cm². Equal numbers of animals were sham irradiated in each group. Quantitative studies of Purkinje cells showed a significant and irreversible decrease in rats irradiated during fetal or fetal and early postnatal life. In animals exposed postnatally, and euthanized immediately after irradiation, significant decrease in the relative number of Purkinje cells was apparent. However, restoration apparently occurred after forty days of recovery.     

Effect of ketamine anesthesia on daily food intake in Macaca mulatta and Cercopithecus aethiops

Ketamine hydrochloride is frequently administered to non-human primates as a means of chemical restraint. This procedure can be a frequent source of stress to monkeys at research facilities, impacting animal health, well-being and research quality. This study was designed to measure ketamine's effect on daily food intake, a parameter that reflects and influences animal well-being and directly impacts research studies. On five occasions, baseline daily food intake was compared to daily food intake occurring 24, 48, 72, 96, and 120 h after an intramuscular injection of 10 mg/kg ketamine in male African green monkeys (AGMs) (Cercopithecus aethiops) and male and female rhesus macaques (Macaca mulatta). AGMs and female rhesus macaques had significantly reduced daily food intake during the first 4 days after receiving ketamine. The AGMs continued to display significantly reduced daily food intake on the fifth day after ketamine. The male rhesus macagues showed a trend toward reduced daily food intake, greatest during the first 2 days and remaining less than baseline intake through the fifth day following ketamine. The degree of observed food intake reduction was most severe at the 24 h (mean percent intake reduction: AGMs: 57%; rhesus males: 48%; rhesus females: 40%) and 48 h time points (AGMs: 24%; rhesus males: 14%; rhesus females: 13%). A subset of the AGMs that did not receive ketamine, but observed other animals in the room receive ketamine, showed reduced food intake at 24 and 48 h after ketamine, though not to the degree associated with ketamine administration. These results indicate that ketamine anesthesia is associated with a prolonged reduction in daily food intake in AGMs and rhesus macaques. Frequent use of ketamine in non-human primates may have a significant impact on animal health and well-being, and alternatives to its use warrant consideration.     

Synthesis of diazoluminomelanin (DALM) in HL-60 cells for possible use as a cellular-level microwave dosimeter

Chemical and bacterial synthesis of a thermochemiluminescent polymer known as diazoluminomelanin (DALM) has been previously reported. This paper focuses on the intracellular synthesis of aminomelanin (AM) in mammalian cell lines and subsequent DALM synthesis from this core molecule. B16 melanoma cells, HL-60 myeloid leukemia cells, and RAW 264.7 macrophages show AM and DALM production. Macroscopic image analysis of HL-60 cell lysates containing DALM using the Quantitative Luminescence Imaging System (QLIS) showed increased chemiluminescence (CL) with increased microwave power input and increased temperature. This work represents a first step toward the goal of microscopic radiofrequency dosimetry of individual DALM-loaded cells using image analysis. © 1994 Wiley-Liss, Inc.