Axillary F-loop latency of ulnar nerve in normal young adults

F waves were studied with stimulation of the ulnar nerve in normal subjects (25 men and 15 women, with an average age of 26.5 years) using an EMG machine that permits the simultaneous display of 8 sweeps. The axillary F-loop latency (AFLL), defined at the conduction time between the axilla (25cm from the sternal notch) and the spinal cord, was 9.17 +/- 0.81msec when 8 F responses were measured but was 8.57 +/- 1.00msec when 40 F responses were used. Data from men and women showed no significant statistical difference. The mean plus 2 standard deviations were 10.8 and 10.6msec for 8 and 40 responses, respectively. On the basis of these findings, an AFLL longer than 11msec should be considered abnormal in the young adult. Four measures repeated at weekly intervals showed no significant difference from week to week, indicating that the technique can be consistently and reliably applied at different times. The average duration of the F complex was 15.78 +/- 2.55msec and was about 80% of the average duration of the M wave.

Immunological detection of metastases from prostatic adenocarcinoma

In six patients with known prostatic adenocarcinoma, extraprostatic (metastatic) tumor was suspected on radiographic or radionucleotide studies. When cytological examination of tissue obtained by needle aspiration or biopsy was nondiagnostic, radial gel immunodiffusion was used to identify the presence of prostatic acid phosphatase in the tissue. Four specimens demonstrated prostate-specific acid phosphatase activity, permitting the diagnosis of metastatic prostatic adenocarcinoma. The technique is simple and highly specific.

In vitro microwave effects on human neutrophil precursor cells (CFU-C)

Human marrow cells were irradiated with 2450-MHz CW microwaves in a fluid-filled waveguide irradiation system. Cell exposure was conducted by placing a marrow cell suspension in 20-microliter glass microcapillary tubes were positioned in the exposure chamber, and irradiated at power densities from 31 to 1,000 mW/cm2 (with corresponding specific absorption rates of 62 to 2,000 mW/g) for 15 minutes. The temperature of the sample was maintained at a fixed point. Sham-irradiated (SI) and microwave-irradiated (MWI) cells were cultured in a methylcellulose culture system for neutrophil colony proliferation. There was no reduction in neutrophil colony number on days 6-7 or 12-14 in cells exposed at 31 or 62 mW/cm2, but as the power density was increased to 1,000 mW/cm2, there was a reduction in colony number of MWI cells compared with SI cells. The microwave interaction with the human neutrophil colony-forming cells was apparently not related to temperature rise, or to the state of cells cycle, and was irreversible.

Purification and partial characterization of a preneoplastic antigen in liver carcinogenesis

A preneoplastic antigen has been isolated from the microsomal fraction of the hyperplastic nodules of rat liver. During the purification, the presence of preneoplastic antigen was monitored by microcomplement fixation test and double immunodiffusion plate following reaction with antiserum specific for this antigen. The antigen was purified by seven steps with a purification factor of 167 and 11% yield. It migrated as a single protein band, both in nondenaturing and denaturing polyacrylamide gel electrophoresis; showed a single sharp peak in an isoelectric focusing column at pH 4.75; and had a single serine amino-terminal amino acid. In the absence of detergent during purification, this protein tends to form molecular aggregates. It appears to be a glycoprotein based on the positive periodic acid-Schiff stain and absorption by concanavalin A:Sepharose affinity column chromatography. Amino acid analysis indicated that the protein is acidic, having acidic amino acids (aspartate and glutamate) and basic amino acids (lysine, arginine, and histidine) in a ratio of 6.8. An estimate of the molecular weight by gel filtration gave a value of 145,000 and a calculated Stokes radius of 41.5 A. Electrophoresis under denaturing conditions on sodium dodecyl sulfate-polyacrylamide gel indicated that this protein is a dimer consisting of two subunits of equal molecular weight (M.W. 74,000). Circular dichroism spectra indicated alpha-helix contents at 298 and 222 nm of 25.5 and 28.3%, respectively. A similar protein is present in the endoplasmic reticulum of normal rat liver, but in a much lower concentration.

Studies on microwave and blood-brain barrier interaction

This investigation was aimed at correlating changes of blood-brain-barrier permeability with the quantity and distribution of absorbed microwave energy inside the brain of adult Wistar rats anesthetized by sodium pentobarbital. Through use of thermographic methods and a direct-contact applicator at the animal's head, the pattern of absorbed microwave energy was determined. Indwelling catheters were placed in the femoral vein and in the left external carotid artery. Evans blue and sodium fluorescein in isotonic saline were used as visual indicators of barrier permeation. Exposure to pulsed 2,450-MHz radiation for 20 min at average power densities of 0.5, 1, 5, 20, 145 or 1,000 mW/cm2, which resulted in average specific absorption rates (SARs) of 0.04, 0.08, 0.4, 1.6, 11.5 or 80.0 mW/g in the brain, did not produce staining, except in the pineal body, the pituitary gland, and the choroid plexus - regions that normally are highly permeable. Except for these regions, staining was also absent in the brains of sham-exposed animals. The rectal temperature, as monitored by a copper-constantan thermocouple, showed a maximum increase of less than 0.75 degrees C from a mean pre-exposure temperature of 36.6 degrees C. The highest brain temperature recorded in a similar group of animals using a thickfilm carbon thermistor was less than 41.0 degrees C.

Microwave-evoked brainstem potentials in cats

Rectangular pulse-modulated microwave radiation has been shown to produce auditory responses in mammals. It is therefore reasonable to explore the possibility of using microwave pulses to achieve an estimate of sensori-neural involvement in the objective evaluation of human hearing and to assess the presence of tumors or brainstem lesions in patients with neurological disorders. In this paper we shall show that microwave-evoked auditory response of cats closely resembles that evoked by acoustic pulse. We shall also give preliminary results obtained from electrodes fastened to the vertex of the skull after successive coagulative production of lesions in the inferior colliculus, lateral lemniscus, and superior olivary nucleus.

Health aspects of radio and microwave radiation

Recent publications are selectively reviewed to indicate the characteristics of radio and microwave interaction with biological systems. The emphasis is on low-level effects that occur at or below the currently accepted safety standard. This information is then used to examine the adequacy of existing emission and exposure standards for controlling the environmental levels of radio and microwave radiation, and safeguarding the general population from the deleterious effects resulting from typically encountered exposure in the United States.

In vivo growth of human bladder cancer cell lines

Two human bladder cancer cell lines grew predictably in rats immunosuppressed with antilymphocyte serum. Intraperitoneal inoculation of tumor cell suspensions resulted in diffuse intraabdominal carcinomatosis with consequent host death after 10 to 20 days. Subcutaneous inoculation of tumor cell suspensions resulted in local tumors which grew exponentially for 20 to 30 days before eventual regression after 40 to 50 days; lung metastases developed in at least 13 per cent of the animals with subcutaneous tumors. The histologic appearance of the xenografted tumors closely resembled that of the original tumors. Subsequent in vitro culture of the xenografted tumors provided cell lines that were morphologically identical to the primary lines and that retained a human karyotype. It is proposed to employ this model of human bladder cancer to evaluate chemotherapeutic agents for possible use in the clinical disease.

Salt extraction of chromatin from normal diploid and SV-40 transformed human fibroblasts

Regulation of cell proliferation is a complex but exceedingly interesting form of gene expression. Overwhelming evidence in the past ten years has shown that the flow of cells through the cell cycle, and the regulation of cell population density, are under the control of the eukaryotic genome. Changes in the function and structure of chromatin have been reported when G0 cells are stimulated to proliferate and when continuously dividing cells move through the different phases of the cell cycle from G1 to S, G2 and mitosis. The changes occurring in the structure and function of chromatin seem to be related to changes occurring in the chromosomal proteins, especially non-histone chromosomal proteins and chromatin-bound protein kinases. Studies are now in progress to isolate the genes, with their respective proteins, that regulate the different steps of the cell cycle.

Microwave-induced hearing: some preliminary theoretical observations

Pulsed microwaves impinging on the head of animals and man produce auditory sensations. Theoretical analyses indicate a series of resonant frequencies occurring inside the head. This is supported by previous observations of characteristic oscillations recorded from the round window of mammals during pulsed microwave irradiation.

Effects of prolonged quiescence on neuclei and chromatin of WI-38 fibroblasts

DNA synthesis and cell division are markedly reduced in confluent mono-layers of WI-38 diploid fibroblasts, but resume again if the depleted medium is replaced by fresh medium containing 10% fetal calf serum. If the cells are kept quiescent for prolonged periods of time after confluence (1 or 2 weeks), the fraction of cells that can be stimulated to proliferate by fresh serum decreases and the length of the prereplicative phase increases. The template activity of isolated nuclei decreases with increasing time of quiescence, and parallel changes occur in chromatin as evidenced by circular dichroism spectra and capacity to bind the intercalating dye, ethidium bromide. When WI-38 cells are stimulated to proliferate after prolonged quiescence, the increase in template activity of nuclei is delayed by several hours in comparison to cells stimulated after short periods of quiescence. Two distinct steps, both requiring serum, can be identified in the prereplicative phase of cells stimulated to proliferative after prolonged quiescence. We interpret the results as indicating that, during prolonged quiescence, WI-38 fibroblasts go into a deeper GO state from which they can be rescued only after prolonged stimulation. In this respect, prolonged quiescence may bear some resemblance to the process of aging.

Microwave auditory effect- a comparison of some possible transduction mechanisms

When human subjects are irradiated with pulse modulated microwave energy they report the perception of a sound that appears to originate from within or slightly behing the head. Three of the possible mechanisms are examined using first order mathematical approximations and several simplifying assumptions. The results show that while all three (radiation pressure, strictive force and thermal expansion) are capable of producing the phenomenon, the stress resulting from thermal expansion may be so great that it masks the effect of the others completely.

Coupling of Gaussian electromagnetic pulse into a muscle-bone model of biological structure

The effect of angle of incidence on the transmission electromagnetic pulse with Gaussion character in biological material is studied. The model assumed is a layer of soft tissue over a semi-infinite medium of boney structure governed by alpha dispersion. The numerical results demonstrate that the transmitted pulse strength is the greatest when the pulse is incident normally on the air-tissue interface. The coupling efficiency for a one microsecond pulse is three times as big as that for a ten microsecond pulse.