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Biomedical subjects

D I McRee

Publications and source records attributed to D I McRee.

At least 37 records · Page 2Linked to original sources
PubMed1986

Elimination of microwave effects on the vitality of nerves after blockage of active transport.

We have previously reported that exposure to microwave fields (a specific absorption rate of 10 W/kg at 2.45-GHz continuous wave) would consistently lower the survival time of isolated frog sciatic nerves stimulated at high repetition rates (50 pulse pairs per second, ppps). The time course of the loss of excitability of the exposed nerve (as compared to its unexposed contralateral mate) is reminiscent of that seen when the active transport of sodium (Na) and potassium (K) is blocked by certain agents--such as the cardiac glycoside ouabain. To assess the role that these microwaves may have in interfering with or counteracting active transport, we performed a series of experiments in which the active Na-K pump was substantially blocked by ouabain prior to microwave exposure. The paired nerves were soaked for 5 min in a high concentration (10(-3) g/liter) of ouabain to achieve the fastest and most complete blockage of the Na-K pump prior to stimulation at 50 ppps. The "rundown time course" was, as expected, accelerated in all ouabain-treated nerves, but the microwave-exposed nerves showed no additional shortening of survival time. The experiments were repeated at a slower stimulation rate (5 ppps) so that the survival time of the nerves more closely approximated that of nerves not treated with ouabain (1 to 2 h versus 30 min or less for ouabain-treated nerves stimulated at 50 ppps). Results of these lower stimulation rates also showed that there was no significant difference in the survival time of ouabain-treated exposed and control nerves. These results lend support to the view that the relative loss of excitability in microwave-exposed nerves is related to an interference with or counteraction of the Na-K pump.

Action Potentials↗
PubMed1985

Hematological response of Japanese quail to acute hemorrhagic stress.

Hematological and serum biochemical changes in response to hemorrhagic stress were determined in both sexes of juvenile and adult Coturnix coturnix japonica over 3 day period following a mechanical hemorrhage of 30% of the calculated total blood volume. There was an initial shift posthemorrhage towards greater numbers of more mature erythrocytes and fewer circulating reticulocytes. Reticulocytosis was indicated 48-72 hr posthemorrhage. Glucose and lactic acid dehydrogenase levels increased after hemorrhage. Serum beta-glucuronidase was elevated only in adults. Japanese quail seemed to recover from hemorrhage more rapidly than had been reported for chickens, other birds and mammals.

Aging↗
PubMed1985

Hematological response of immunized and serially bled Japanese quail.

Sexually mature female Japanese quail (Coturnix coturnix japonica) were immunized by an intravenous injection with .5 ml of a 7.5% suspension of Chukar partridge (Alectoris graeca chukar) red blood cells (CRBC). Blood samples were collected either serially from one group of quail or a single time from separate groups of quail at 0 (nonimmunized), 3, 6, and 9 days post-immunization. Total anti-CRBC hemagglutinin titers (HA) were measured by a microhemagglutinin procedure. Selected hematological variables were also measured. Mean HA was not affected by serial blood sampling. Total erythrocyte numbers, percent hematocrit, and hemoglobin levels were depressed in serially bled quail at 3 days postimmunization. Reticulocytosis was found in serially bled quail at 6 days postimmunization.

Animals↗
PubMed1985

Effect of phlebotomy on reticulocyte numbers in Japanese Quail.

Hematological changes were studied in response to a phlebotomy of 30% of the estimated total blood volume in 5-week-old Coturnix coturnix japonica. Blood samples, femoral bone marrow samples, and blood and marrow erythroid cell differential counts were collected at 0 (nonphlebotomized), 1, 3, 6, 24, and 72 hr postphlebotomy. The samples were collected only once from each bird. Total peripheral erythrocyte numbers, percent hematocrit, and hemoglobin levels were decreased at 1, 3, 6, and 24 hr. The relative percentage of peripheral erythrocytes with little or no reticulum was not affected by phlebotomy. With the exception of mean cellular hemoglobin concentration, all of the hematological values measured in the peripheral blood had returned to nonphlebotomized, 0 hr levels at 72 hr postphlebotomy. However, in the bone marrow, a marked reticulocytosis was found at 72 hr postphlebotomy.

Animals↗
PubMed1985

Teratogenic, biochemical, and histological studies with mice prenatally exposed to 2.45-GHz microwave radiation.

Pregnant CD-1 mice were exposed to 2.45-GHz continuous wave microwave radiation at an incident power density of 30 mW/cm2. The local specific absorption rate near the uterine area (deep colonic location), as determined from time-temperature profiles measured with a Vitek thermistor probe, was 40.2 mW/g. Groups of mice were exposed 8 hr per day through Days 1-6 or 6-15 of pregnancy. Other groups of animals were exposed to an elevated ambient temperature of 31 degrees C which increased the colonic temperature 2.3 degrees C, the same as that produced by the microwaves. Sham-irradiated groups of animals were treated exactly the same as the microwave-exposed animals. For the two conditions, temperature exposed and sham exposed, two groups of animals were used. One group was handled in the same manner as the microwave-irradiated group and the other group was not handled so as to evaluate the effects of stressing the animals by handling. Eleven groups of animals were used in the complete study: five groups for gestational Days 1-6, five groups for gestational Days 6-15, and one group of cage control animals. On Day 18 of gestation the dams of all experimental groups were sacrificed and their reproductive status was determined. The fetuses were examined for visceral and skeletal alterations. Brain cholinesterase activity and histology were evaluated in the groups exposed on Days 6-15. The results show that microwave radiation increases embryo lethality at the early stages of gestation (exposure Days 1-6). Fetal toxicity and teratogenicity were not significantly increased by exposure to microwaves on either Days 1-6 or 6-15 of gestation. Cholinesterase activity and histology of the brain of 18-day-old fetuses were not adversely affected.

Abnormalities, Radiation-Induced↗
PubMed1984

In vitro effects of microwave radiation on rat liver mitochondria.

Liver mitochondria were exposed in vitro at 30 degrees C to microwave radiation (2.45 GHz) during the following states of respiration: resting, state 1; substrate dependent, state 2; ADP stimulated, state 3; and ADP depleted, state 4. At 10 or 100 mW/g, with succinate as substrate, no effect of exposure was observed on states 1-4 or the respiratory control index (state 3/state 4) of either tightly or loosely coupled mitochondria. When glutamate was used as substrate, no effects were observed at 10 mW/g. However, in the loosely coupled mitochondria the 100 mW/g exposure produced an increase in states 2 and 4 and a decrease in the respiratory control index. The results suggest that the function of loosely coupled mitochondria can be affected at high power levels of microwave radiation.

Animals↗
PubMed1984

Whole-body and local dosimetry in rats exposed to 2.45-GHz microwave radiation.

Rat cadavers oriented parallel to the electric field were exposed to 2.45-GHz microwave radiation. The weights of the cadavers ranged from approx. 5 to 320 g and their lengths ranged from approx. 5 to 21.5 cm. Whole-body specific absorption rates (SAR) were measured using calorimetric techniques, and local specific absorption rates were obtained from time-temperature profiles measured with a non-interacting thermistor probe (Vitek). The whole-body SARs decreased by a factor of 12 in rat pups weighing 5 g as compared to adult rats weighing 320 g. The local SARs in the colon were slightly higher than the whole-body SARs for animals in the weight range from 40 to 320 g and approx. 2.5 times higher in animals ranging from 10 to 30 g. The local SARs in the brain were two to three times higher than the whole-body SARs for animals ranging in weights from 20 to 320 g. The data show that it is important to measure both whole-body SARs and local SARs when conducting experiments to determine biological effects in order to adequately explain any biological changes and to extrapolate data from different sizes and species of animals.

Animals↗
PubMed1984

Effect of 2450 MHz microwave radiation on hematopoiesis of pregnant mice.

In this study, the influence of 2450 MHz CW microwave radiation on hematopoiesis in pregnant mice was examined. Dams (mice CD-1 strain) were irradiated during Days 1-6 or 6-15 of pregnancy. The animals were irradiated for a total of 8 hr per day (two 4-hr exposures in 9 hr) at an average power density of 30 mW/cm2. Peripheral blood and bone marrow samples were obtained on Day 18 of pregnancy. The total leukocyte and differential leukocyte counts of peripheral blood samples were not affected by either exposure regimen. In addition, no effects were noted in either the erythroid or myeloid mitotic indices of bone marrow samples. Exposure of pregnant mice to microwave radiation under the conditions of these experiments had no effects on the investigated aspects of hematopoiesis.

Animals↗
PubMed1983

Influence of in vitro microwave radiation on the fertilizing capacity of turkey sperm.

Turkey sperm were exposed to 2.45-GHz microwave radiation in a temperature-controlled wave-guide apparatus. Temperature was maintained at either 25 or 40.5 degrees C. The sperm were exposed for 30 min at a specific absorption rate (SAR) of 10 or 50 mW/g. Following irradiation, the sperm were used to inseminate virgin turkey hens artificially. During the 9 weeks following the single insemination, the following were assessed: mean number of eggs, percentage of fertile eggs, rate of decrease in egg fertility, percentage of hatched eggs, and percentage of early and late deaths. These data demonstrate that, for the conditions used in these experiments, microwave radiation has no effect on the fertilizing capacity of turkey sperm.

Animals↗
PubMed1983

Effect of 2,450 MHz microwave radiation on the development of the rat brain.

Male Sprague-Dawley rats were exposed to 2,450 MHz microwave radiation at an incident power density of 10 mW/cm2 daily for 3 hours from day 4 of pregnancy (in utero exposure) through day 40 postpartum, except for 2 days at the perinatal period. The animals were killed, and the brains removed, weighed, measured, and histologically examined at 15, 20, 30, and 40 days of age. The histologic parameters examined included the cortical architecture of the cerebral cortex, the decline of the germinal layer along the lateral ventricles, the myelination of the corpus callosum, and the decline of the external germinal layer of the cerebellar cortex. In 40-day-old rats, quantitative measurements of neurons were also made. The spine density of the pyramidal cells in layer III of the somatosensory cortex, and the density of basal dendritic trees of the pyramidal cells in layer V were measured in Golgi-Cox impregnated specimens. In addition, the density of Purkinje cells and the extent of the Purkinje cell layer in each lobule were measured in midsagittal sections of the cerebellum stained with thionin. There were no remarkable differences between microwave-exposed and control (sham-irradiated) groups for any of the histologic or quantitative parameters examined; however, the findings provide important information on quantitative measurements of the brain. The data from this study failed to demonstrate that there is a significant effect on rat brain development due to microwave exposure (10 mW/cm2) during the embryonic, fetal, and postnatal periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Effects of 2450 MHz microwave radiation during the gestational period on the postnatal hematology of rats.

Pregnant Sprague-Dawley rats were exposed to 2.45 GHz CW radiation for 3 h daily from day 4 through day 20 of pregnancy at an average power density of 10.3 mW/cm2. At 2, 10, 20, and 30 d postpartum, several aspects of peripheral blood hematology of male and female pups were examined. No effects were noted on pregnancy rate or litter size; however, pup weight was reduced. Also, the white blood cell numbers were lower in male and female pups exposed to microwave radiation and the differential cell counts were altered in the female pups at 10 d postpartum. At 30 d of age, no differences were noted between the sham and exposed pups for any of the hematologic variables examined.

Animals↗
PubMed1983

Reproduction in male Japanese quail exposed to microwave radiation during embryogeny.

Japanese quail (Coturnix coturnix japonica) embryos were exposed continuously to 2.45 GHz CW microwave radiation during the first 12 days of embryogenesis. The incident power density was 5 mW/cm2, and the specific absorption rate (SAR) was 4.03 mW/g. At 23 weeks of age an assessment of the reproductive capacity of the males was performed. Spermatozoal numbers and motility in semen samples which were collected manually were reduced significantly (P less than or equal to 0.01). However, spermatozoal viability and gross morphological characteristics in the exposed birds were not consistently different from the controls. Relative testicular weights were not altered significantly in the exposed males. Percentage of fertile eggs was significantly reduced when exposed males were mated to sham control females. The percentage of fertile eggs obtained from mating exposed males with sham control females was 72.5%, while the percentage of fertile eggs from mating of sham control males with sham control females was 80.4%. These data indicate that reproductive capacity in male Japanese quail is reduced when the birds are exposed to 2.45 GHz CW microwave radiation during embryogenesis.

Animals↗
PubMed1982

Influence of 2.45-GHz CW microwave radiation on spontaneously beating rat atria.

The chronotropic and inotropic effects of 2.45-GHz continuous wave (CW) microwave radiation were investigated in the isolated spontaneously beating rat atria. Isolated atria were placed in specially designed tubes inserted into a waveguide exposure system. The atria were then irradiated for a period of 30 min, followed by a 30-min recovery period. The control atria were prepared simultaneously and sham exposed. Experiments were conducted at two temperatures, 22 and 37 degrees C, and two specific absorption rates, 2 mW/g and 10 mW/g. At both temperatures the rate of atrial contraction was not altered by a 30-min exposure at either 2 or 10 mW/g. The average rate (beats per min) was approximately 100 for both the control and exposed atria at 22 degrees C and 215 beats per min for both the control and exposed atria at 37 degrees C. In addition, no inotropic effects on the spontaneously beating atria were noted at any exposure level. These data suggest that 2.45-GHz CW microwave radiation at these intensities has no overt effect on these variables in isolated rat atria.

Animals↗
PubMed1982

Lack of effect of 2.45-GHz microwave radiation on the development of preimplantation embryos of mice.

The development of preimplantation embryos after exposure to microwave radiation was studied. Female CD-1 mice were induced to superovulate, mated, and exposed to 2.45-GHz microwave or sham radiation for 3 h at power densities of 9 mW/cm2 and 19 mW/cm2 on either day 2 or 3 of pregnancy (plug day was considered day 1). Another group of mice was exposed to heat stress by placing the dams in an environmental room at an ambient temperature of 38 degrees C and relative humidity at 62% for 3 h on day 2 of pregnancy. All groups were euthanized on day 4 of pregnancy and embryos were recovered by flushing excised uterine horns. Embryos were examined for abnormalities and classified by the developmental stages. They were then treated with hypotonic solution and dissociated for counting blastomeres. Heat stress caused stunted development of embryos, but no remarkable effect of microwave radiation could be found on the development of preimplantation embryos.

Animals↗
PubMed1982

Effects of 2.45 GHz microwave radiation on the development of Japanese quail cerebellum.

Fertilized Japanese quail eggs were continuously exposed to 2.45 GHz microwave radiation from day 1 through day 12 of incubation at a power density of 5.0 +/- 0.52 mW/cm2 (mean specific absorption rate = 4.03 mW/gm). In the experiment with embryos, irradiated and control embryos were removed from eggs on day 12, 13 or 14 of incubation and the cerebella were histologically examined. In order to examine the long-term effect of microwave radiation during embryogenesis on the cerebellum, some of the quail were allowed to hatch and were reared to eight weeks of age. Their cerebella were histologically examined, and the extent of dendritic arbores, the length of the stem of the primary dendrite, and the size of the perikaryon of Purkinje cells were measured in Golgi-Cox impregnated sections. In the irradiated embryos, a slight developmental retardation was found in the cerebellar cortices in terms of several morphological parameters. The effects included the growth and subsequent decline of the external granular layer, the growth of the molecular layer, the cellular differentiation and the alignment of Purkinje cells, and the accumulation of granule cells beneath the Purkinje cell layer, as well as lower body and brain weights. In the eight-week-old quail, no significant differences were noted between irradiated and control cerebella in the morphological measurements of Purkinje cells.

Animals↗
PubMed1982

Interaction of microwave radiation with turkey sperm.

Turkey sperm were exposed to 2.45 GHz microwave radiation in a temperature controlled waveguide apparatus. Temperature was maintained at 40.0 +/- 0.5 degrees C. The sperm were exposed for 30 min to a specific absorption rate (SAR) of 1, 10, or 50 mW/g. Before and following microwave exposure the following parameters were examined: percentage viability, percentage abnormal sperm, and release of the enzymes lactate hydrogenase (LDH) and glutamic oxalic transaminase (GOT). These parameters were not altered significantly by microwave exposure under the conditions tested.

Animals↗