Microwave-induced changes in nerve cells: effects of modulation and temperature

Helix aspersa neurons were irradiated with continuous-wave (CW) and noise-amplitude-modulated microwaves (carrier frequency 2450 MHz, 20% AM, 2 Hz-20 kHz) in a specially designed waveguide exposure system. Continuous-wave microwave irradiations were conducted at 8 degrees, 21 degrees, and 28 degrees C, while noise-modulated irradiation was performed at 21 degrees C. The results showed that exposure of snail neurons to CW microwaves for 60 min at 12.9 W/kg inhibited spontaneous activity and reduced input resistance at 8 degrees and 21 degrees C but not at 28 degrees C. The relative decrease in resistance at 21 degrees C was half that at 8 degrees C. Exposure of neurons to noise-modulated microwaves at 6.8 and 14.4 W/kg predominately caused excitatory responses characterized by augmented membrane resistance and the appearance of greater activity. The effect differed qualitatively from the inhibition observed with continuous, unmodulated microwave irradiation.

Effect of (E)-5-(2-bromovinyl)-2'-deoxyuridine on replication of Epstein-Barr virus in human lymphoblastoid cell lines

The effect of (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) on replication of Epstein-Barr virus (EBV) was investigated and compared with Acyclovir (ACV). Both drugs inhibited EBV replication very rapidly. However, the inhibitory effect of ACV was readily reversed after removal of the drug, in contrast to the more prolonged effect exerted by BVDU, which persisted for more than 21 days. The 50% inhibitory doses of BVDU for virus replication (ED50) and lymphoblastoid cell growth (ID50) were 0.06 microM and 390 microM, respectively; the in vitro therapeutic index (ID50/ED50) was 6,500. Synthesis of EBV-induced polypeptides with molecular weights of 145K, 140K and 110K was partially reduced by BVDU. When superinfected Raji cells were exposed to 125I-labeled (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU), larger amounts of (125I)IVDU were incorporated into viral DNA than cellular DNA.

Pathophysiologic mechanisms of cardiac tamponade and pulsus alternans shown by echocardiography

A pericardial effusion is easily recognized by echocardiography, but the diagnosis of cardiac tamponade by echocardiography is controversial. Recently, several reports have indicated that right ventricular (RV) or right atrial (RA) diastolic collapse represent highly specific and sensitive signs of a hemodynamically significant pericardial effusion. This report evaluates the pathophysiologic significance of these findings in 3 patients. One patient had classic clinical and hemodynamic features of tamponade without typical echocardiographic features; 1 had typical echocardiographic features of tamponade without the characteristic clinical or hemodynamic features; and 1 had all the findings characteristic of tamponade, including mechanical and electrical alternans. The first patient had increased right-sided cardiac pressures and RV hypertrophy, which prevented RV or RA collapse. The second patient had low right-sided intracardiac pressures, which allowed RV and RA diastolic compression to occur during early and mid-diastole. In the third patient, severe holodiastolic impairment of right-sided filling, and presumed decreased pulmonary venous and pericardial compliance, in the setting of tamponade produced a beat-to-beat alternation of RV and left ventricular filling with associated electrical and mechanical alternans. RV or RA collapse during diastole occurs when intrapericardial pressure equals or exceeds intracardiac pressure. Increases in wall stiffness of chamber pressures may prevent diastolic collapse in the setting of tamponade. Conversely, extremely low intracardiac pressures may allow diastolic collapse to occur in the absence of overt cardiac tamponade. The extent and timing of the RA or RV collapse, rather than its mere occurrence, are important in the diagnosis of cardiac tamponade by echocardiography.

Prolonged inhibitory effect of 9-(1,3-dihydroxy-2-propoxymethyl)guanine against replication of Epstein-Barr virus

The effects of 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG), a new antiviral drug, and acyclovir (ACV) [9-(2-hydroxyethoxymethyl)guanine] on the replication of Epstein-Barr virus (EBV) were compared. Both drugs inhibited EBV DNA replication in P3HR-1 cells and superinfected Raji cells, but neither inhibited replication of the plasmid form of the EBV genome in latently infected Raji cells. However, DHPG had a more prolonged inhibitory effect than ACV. Although the effect of the drugs is prompt, the kinetics of inhibition of EBV replication indicated that a drug exposure of 14 days was needed to reduce the EBV genome copy number to the residual plasmid level (30 copies per cell). The inhibitory effect of ACV was readily reversed within 11 days after removal of the drug, in contrast to the more prolonged effect exerted by DHPG, which persisted for more than 21 days. The 50% inhibitory doses for cell growth of ACV and DHPG were estimated to be 250 and 200 microM, respectively. The viral 50% and 90% effective doses of inhibition were, respectively, 0.3 and 9 microM for ACV and 0.05 and 3 microM for DHPG. The therapeutic indices (50% inhibitory dose/50% effective dose) for ACV and DHPG were 833 and 4,000, respectively. Synthesis of EBV-associated polypeptides was also affected. In superinfected Raji cells, ACV (100 microM) and DHPG (30 microM) inhibited synthesis of polypeptides with molecular weights of 145,000 and 140,000; in addition, synthesis of polypeptides with molecular weights of 110,000 and 85,000 was markedly reduced by DHPG but not by ACV. However, after drug removal, the inhibitory effect of ACV on polypeptide synthesis was abolished in contrast to the more persistent effect of DHPG.

Histopathological and biochemical analyses of transplantable renal adenocarcinoma in rats induced by N-ethyl-N-hydroxyethylnitrosamine

Transplantable renal adenocarcinoma can be readily induced in Wistar strain male rats by initiation with N-ethyl-N-hydroxy-ethylnitrosamine followed by promotion with beta-cyclodextrin. The transplantability rates of the tumors by s.c. inoculation in newborn rats were 33 and 50%, respectively, for tumors of the first and second passages, and 100% for both third and fourth passages. The transplantability rates were affected by route of inoculation; rates of 50 and 100% were observed for s.c. and i.p. inoculations, respectively. The growth rate of tumors induced by i.p. inoculation was 3-fold higher than that induced by s.c. injection. Macroscopically, most of the tumors grew in the s.c. tissue of inoculation sites. However, invasive growth of tumors in spleen, liver, stomach, peritoneum, and intestine were seen in 50% of the animals inoculated i.p.; metastatic cancers to lung were seen in 16%. Histologically, the tumors were well-differentiated adenocarcinomas composed of uniform cells resembling kidney tubular cells and appeared to be derived from normal kidney tissues. A 5-fold decrease in gamma-glutamyl transferase activity in tumor tissues was found as compared with that of nontumorous kidney tissues. Electrophoretic analysis of cellular proteins in polyacrylamide gels revealed that tumor tissues exhibited five new polypeptides with molecular weights of 81,000, 64,000, 59,000, 50,000, and 36,000 which were either lacking or undetectable in the nontumourous area and control kidney. In addition, protein banding patterns of transplantable renal tumor appeared to be more heterogeneous than those of primary kidney tumor.

Antagonistic action of retinoic acid against teleocidin and 12-O-tetradecanoyl-phorbol-13-acetate on activation of Epstein-Barr virus genomes

Teleocidin, a new potent tumor promoter, produces biological effects similar to 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on human lymphoblastoid cell lines. A wide range of concentrations (4-16 ng/ml) of teleocidin were optimal for induction of replication of latent Epstein-Barr virus (EBV) genomes in P3HR-1 cells; cell growth was significantly inhibited in this dose range. In contrast, treatment of Raji cells with an identical dose range of teleocidin did not induce replication of latent EBV genomes. As with TPA, P3HR-1 cells in the stationary phase were twice as responsive to teleocidin induction as exponentially growing cells. The activation of P3HR-1 cells both by teleocidin and TPA greatly enhanced the synthesis of EBV DNA and EBV-associated polypeptides as determined by cRNA - DNA hybridization and by analysis on polyacrylamide gels. Both drugs also increased production of biologically active virus as monitored by the synthesis of viral DNA in superinfected Raji cells. These effects were completely inhibited by retinoic acid. However, retinoic acid did not inhibit the spontaneous viral DNA replication that occurs in P3HR-1 cells not treated with the inducers. Thus, it appears that retinoic acid antagonizes the inducing effects of TPA and teleocidin, but not viral replication itself.

Cerebrovascular permeability to 86Rb in the rat after exposure to pulsed microwaves

Microwaves (pulsed, 2,450 MHz) at an average power density of 3 W/cm2 were applied directly to the head for 5, 10, or 20 min, producing a peak specific absorption rate of 240 W/kg in the brain, which, after a 10-min exposure, resulted in brain temperatures in excess of 43 degrees C. A bolus of 86Rb in isotonic saline was injected intravenously and an arterial sample was collected for 20 s to determine cardiac output. Compared with unexposed controls, uptake of 86Rb increased most in those regions directly in the path of the irradiation, namely, the occipital and parietal cortex, as well as the dorsal hippocampus, midbrain, and basal ganglia. In a separate group of animals, regional brain-vascular spaces were found to increase with brain temperature. These results support previous observations indicating that reliably demonstrable increases of blood-brain barrier permeability are associated with intense, microwave-induced hyperthermia, and that the observed changes are not due to field-specific interaction.

Expression and regional assignment of Chinese hamster ESD and rRNA genes associated with translocations giving rise to chromosomes Z1 and Z6 in CHO cells

The Chinese hamster genes ADK, NP, ESD, PGM2, PEPS, PEPB, GLO, and GSR, all of which are on Chinese hamster chromosome 1, were assigned to CHO-LA chromosomes by analysis of the segregation of CHO isozymes and chromosomes from interspecific somatic cell hybrids made with CHO cells and mouse C11D cells. One allele of each of these eight loci remained linked on the normal chromosome 1 homolog. For seven loci, the other allele remained linked on chromosome Z1, but ESD was shown to have been translocated to chromosome Z6 (Chinese hamster chromosome 5q +). Ag-NOR staining of CHO chromosomes indicated that the (1;5) translocation was very likely reciprocal, since the Chinese hamster chromosome 5, which gave rise to the CHO Z6, lacks an NOR and the Z1 now has one. These data allowed regional assignment of ESD to the distal portion of Chinese hamster chromosome 1p and provided genetic evidence for the origin of CHO chromosomes Z1 and Z6 from Chinese hamster chromosomes 1 and 5. Induced electrophoretic shift mutations of ESD and positive Ag-NOR staining for the rRNA genes on the Z1 showed that the activities of the genes lying close to the translocation breakpoints were maintained.

Acyclovir and Epstein-Barr virus infection

Acyclovir (ACV) has an ED50 of 0.3 microM against EBV replication in vitro. Based on these and other data we carried out a pilot, double-blind, placebo-controlled trial of ACV for treatment of infectious mononucleosis. Only patients with relatively severe illness requiring hospital management were enrolled. Ten subjects with proven infectious mononucleosis received placebo and 10 ACV. The drug was administered intravenously at 8-hourly intervals in a total daily dosage of 1500 mg/m2 for 5 days. Preliminary analyses of the results indicate that the drug interrupted virus excretion in the oropharynx transiently but had no effect on ability to generate lymphocytic lines from peripheral blood. Symptoms and signs unaffected by ACV were splenomegaly, lymphadenopathy, lethargy, fever and pharyngitis. There was significantly more rapid regain of weight in the ACV-treated group. On the basis of these results we have instituted an out-patient trial of orally administered ACV in patients with less severe illness earlier in its course. We have also begun in-vitro tests of other drugs that might prove to be effective against Epstein-Barr virus infection, and have shown that 9-1 (1,3-dihydroxy-2-propoxymethyl)guanine (BW759) has an ED50 of 0.05 microM.

Hydrogen peroxide contrast echocardiography

Several agents are used as echocardiographic contrast agents, but their unreliability discourages routine clinical use. Studies from the early 1960s suggest that dilute hydrogen peroxide (H2O2) is a safe intravascular agent. Its use was evaluated in contrast echocardiography. To obtain dense opacification reliably, H2O2 (3%) was passed through a sterile 0.2 micron Millipore filter and diluted with heparinized saline solution to make a 0.1 to 0.2% solution. A drop of blood was withdrawn from an indwelling peripheral venous needle into a syringe containing 0.5 to 2.0 ml of the dilute H2O2 and the contents injected. Studies in dogs, normal adults and 36 patients with noncyanotic congenital and acquired cardiac disorders produced dense opacification with no complications. In vitro mixture of H2O2 (0.3%) with leukocyte-poor blood or plasma produced only a few microbubbles, while addition to whole blood or buffy coat produced many, suggesting a role for leukocyte peroxidase. H2O2 contrast echocardiography is simple, inexpensive, and reliably provides dense, sustained opacification. This study and previous studies suggest that intravenous injection of 0.2% H2O2 can be done safely. Great caution should be exercised in patients with severe pulmonary hypertension or large right-to-left shunts because little clinical experience with H2O2 is available.

Epstein-Barr virus: inhibition of replication by three new drugs

Epstein-Barr virus (EBV) is the cause of infectious mononucleosis and is associated with three human malignancies. Acyclovir [9-(2-hydroxyethoxymethyl)guanine], the first clinically useful drug effective against replication of EBV, is without effect against latent or persistent EBV infection. Three nucleoside analogs, E-5-(2-bromovinyl)-2'-deoxyuridine, 1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)-5-iodocytosine, and 1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)-5-methyluracil are potent inhibitors of EBV replication in vitro. Moreover, in contrast to the reversibility of viral inhibition by Acyclovir, these three drugs have prolonged effects in suppressing viral replication even after the drugs are removed from persistently infected cell cultures.

Microwave sensing of increased intracranial water content

A new technique to monitor brain edema is described that uses microwave energy to detect increased intracranial water content. By recording the phase of a transmitted microwave signal, increases in intracranial water content on the order of 1% are detected in vivo. These findings suggest that the progression of brain edema on a long-term basis can be assessed by progression of brain edema on a long-term basis can be assessed by our technique. Furthermore, phase changes related to small intracranial pressure variations are observed, indicating that the detection of pathologic pressure variations such as Traube-Hering-Mayer waves and plateau waves is possible by a noninvasive microwave technique.

Unique spectrum of activity of 9-[(1,3-dihydroxy-2-propoxy)methyl]-guanine against herpesviruses in vitro and its mode of action against herpes simplex virus type 1

A guanosine analog, 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (DHPG), was found to inhibit herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2, cytomegalovirus, and Epstein-Barr virus replication by greater than 50% at concentrations that do not inhibit cell growth in culture. The potency of the drug against all of these viruses is greater than that of 9-[(2-hydroxyethoxy)methyl]guanine (acyclovir). DHPG was active against HSV-1 growth during the early phase of virus replication and had no activity when added at a later time after infection. Its antiviral activity was irreversible. Thymidine partially neutralized its action. The anti-HSV-1 activity of DHPG was dependent on the induction and the properties of virus-induced thymidine kinase. Virus variants that induced altered virus thymidine kinase and became resistant to acyclovir were still as sensitive to DHPG as the parental virus. DHPG is active against five different HSV variants with induced altered DNA polymerase and resistance to acyclovir.

Noninvasive recognition of the parchment right ventricle (Uhl's anomaly arrhythmogenic right ventricular dysplasia) syndrome

The case of a 53-year-old man with right heart failure, selective enlargement of the right-sided cardiac chambers, and recurrent sustained ventricular tachycardia is presented. Echocardiographic, radionuclide ventriculographic, and angiographic studies were typical of the right ventricular abnormalities in Uhl's anomaly; electrocardiographic and electrophysiologic findings were those of arrhythmogenic right ventricular dysplasia. Features of this unusual cause of cardiac failure and ventricular arrhythmias in the adult are reviewed, and compared to previous reports of both Uhl's anomaly and arrhythmogenic right ventricular dysplasia. We postulate that these two syndromes are manifestations of a single, presumably congenital, pathophysiologic process--the "parchment right ventricle" syndrome.

Activation of latent Epstein-Barr virus genomes: selective stimulation of synthesis of chromosomal proteins by a tumor promoter

The tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) is a potent inducer of Epstein-Barr virus (EBV) gene expression. The optimal conditions for maximum activation of latent EBV genomes by TPA were determined. Although TPA is able to induce replication of EBV genomes in P3HR-1 cells in all phases of growth, the greatest increase in viral genome copies per cell (15-fold above the control level) occurred in nonproliferating cells as opposed to cells growing exponentially (6-fold above the control level). The synthesis of chromosomal proteins in nonproliferating cells under the conditions that induce maximum activation of latent virus genomes by TPA was studied. Selective stimulation in chromosomal protein synthesis accompanied the increase in EBV genomes in P3HR-1 cells despite an overall reduction in total cellular protein synthesis. Comparison of the chromosomal proteins from TPA-induced P3HR-1 cells and from superinfected Raji cells revealed comigrating chromosomal polypeptides of 145K, 140K, 135K, 110K, 85K, and 55K that are presumably EBV associated. The selective stimulation of synthesis of these chromosomal proteins in TPA-treated P3HR-1 cells was closely associated with the activation of latent EBV genomes.

Enhancement of replication of Epstein-Barr virus DNA in human lymphoblastoid cell lines by N-methyl-N'-nitro-N-nitrosoguanidine

N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a potent carcinogen that alkylates nucleic acids. Interaction of MNNG with human lymphoblastoid cell lines carrying Epstein-Barr virus (EBV) was studied. Treatment of virus-producing cells (P3HR-1) with MNNG resulted in an approximately 3-fold increase in EBV genome copies per cell as determined by cRNA--DNA hybridization. This effect was not observed in a non-virus-producer line (Raji). Dose-response studies indicated that the optimum concentration was between 0.5 micrograms and 2 micrograms/ml. This same dose range was most effective in inhibiting cell proliferation both of P3HR-1 and Raji cells. Concomitant treatment of P3HR-1 cells with MNNG and 12-O-tetradecanoylphorbol-13-acetate gave an additive increase to 9-fold of the number of EBV genome copies per cell. Pretreatment of Raji cells with MNNG followed by superinfection with P3HR-1 virus resulted in a 35% enhancement of EBV DNA replication as analyzed by density centrifugation. In contrast, Raji cells superinfected with MNNG-treated EBV showed a marked reduction in EBV DNA replication which indicates that the lesions produced in the viral genome by the drug interferred with the infectious potential of the virus.

Acoustical imaging of a model of a human hand using pulsed microwave irradiation

Pulsed 5.66-GHz microwave energy irradiated a model of a human hand that was positioned above a submerged planar array of 400 hydrophones. Hydrophone response data were analyzed by a computer that graphically reproduced the image.

Magnetic necklace: its therapeutic effectiveness on neck and shoulder pain

The effect of the magnetic necklace on chronic neck and shoulder pain was studied on 101 volunteers, 46 males and 55 females. A double-blind method was applied on 4 divided groups (with pain vs without pain matched with magnetic vs nonmagnetic necklace). All the subjects wore the necklace 24 hours per day for 3 weeks. Subjective evaluation from the subjects with pain, either with magnetic or nonmagnetic treatment, was performed before and 3 weeks after the necklace treatment, and revealed a significant placebo effect in terms of decrease in intensity or frequency of pain. The objective tests with electrodiagnostic procedures were done before the treatment and at 3 weekly intervals. The proximal conduction time of the ulnar nerve was significantly reduced by magnetic treatment in the subjects without pain but was not changed in the subjects with pain. There was no significant change in the excitation threshold of the suprascapular nerve in all subjects. The possible mechanism of magnetic effects on pain and the prospect of magnetotherapy for pain relief in physical medicine are discussed.

Rat bladder isograft model for focal carcinoma

A model for focal bladder carcinoma in rats was developed with the use of an isograft technique. Bladder tumors developed by carcinogen induction with FANFT or MNU were grafted to bladders of syngeneic rats. Ninety-six per cent (56 our of 58) of the grafts were taken and 83 per cent (34 out of 41) of the grafted tumors remained neoplastic. Most of the grafts from FANFT-induced tumor remained localized at the original site whereas many from the MNU-induced tumor spread beyond the original graft area. The model system may be useful for the evaluation of chemotherapeutic agents as well as for the studies of basic mechanisms of tumor growth and spreading.