Microscopic and macroscopic tumor and parenchymal effects of liver stereotactic body radiotherapy.

PURPOSE: To describe the histologic and volumetric changes in normal liver tissue after stereotactic body radiotherapy (SBRT) for liver metastases. METHODS AND MATERIALS: Pre- and post-SBRT imaging studies were analyzed to evaluate the effect of SBRT on normal liver volume (NLV) in 15 patients treated in a prospective clinical trial. Two other patients underwent exploratory surgery after SBRT and histologic analyses of the irradiated liver were performed to characterize the pathologic effects of SBRT. RESULTS: In the 15 patients studied quantitatively, the total NLV had decreased transiently at 2-3 months after SBRT and then began to regenerate at 3-8 months after SBRT. The median NLV reduction at the maximal observed effect was 315 cm(3) (range, 125-600) or 19% (range, 13-33%). Among the several dosimetric parameters evaluated, the strongest linear correlation was noted for the NLV percentage receiving 30 Gy as a predictor of maximal NLV reduction (r(2) = 0.72). The histologic changes observed 2 and 8 months after SBRT demonstrated distinct zones of tissue injury consistent with localized veno-occlusive disease. CONCLUSION: The well-demarcated focal parenchymal changes after liver SBRT (demonstrated both radiographically and histologically) within the high-dose zone are consistent with a threshold dose-induced set of phenomena. In contrast, the more global effect of NLV reduction, which is roughly proportional to whole organ dose parameters, resembles more closely an effect determined from radiobiologically parallel architecture. These observations suggest that modeling of normal tissue effects after liver SBRT might require different governing equations for different classes of effects.

Comparison of direct inoculation and Copan transport systems for isolation of Neisseria gonorrhoeae from endocervical specimens.

Two commercial swab transport systems, Copan Amies gel agar with and without charcoal (Copan Diagnostics, Corona, Calif.), were compared to direct inoculation onto modified Thayer-Martin medium for detection of Neisseria gonorrhoeae in 1,490 endocervical specimens obtained from women attending a sexually transmitted disease clinic. Copan swabs were held in the transport system for 24 h at room temperature prior to inoculation onto modified Thayer-Martin medium. All cultures were incubated at 35 degrees C in 5% CO(2), and bacteria were identified on the basis of Gram stain, oxidase, and biochemical reactions. Copan Amies gel agar transport system without charcoal detected 77 of 81 (95%) direct inoculation culture-positive specimens, and Copan Amies gel agar transport system with charcoal detected 53 of 56 (95%) directly inoculated culture-positive specimens. Copan Amies gel agar without charcoal inoculated after 6 h supported growth of 56 (98%) positive cultures out of only 55 directly inoculated culture-positive specimens. This study demonstrates that Copan swabs represent a reasonable alternative, providing convenience, low cost, and ease of use while still maintaining a satisfactory recovery rate of N. gonorrhoeae from clinical specimens, if specimens can be inoculated onto selective media within a relatively short time period not involving overnight shipment.

In vivo localization of [(111)In]-DTPA-D-Phe1-octreotide to human ovarian tumor xenografts induced to express the somatostatin receptor subtype 2 using an adenoviral vector.

Adenoviral vectors, encoding genes for cell surface antigens or receptors, have been used to induce their high level expression on tumor cells in vitro and in vivo. These induced antigens and receptors can then be targeted with radiolabeled antibodies or peptides for potential radiotherapeutic applications. The purpose of this study was to determine a dosing schema of an adenoviral vector encoding the human somatostatin receptor subtype 2 (AdCMVhSSTr2) for achieving the highest tumor localization of [(111)In]-DTPA-D-Phe1-octreotide, which binds to this receptor, in a human ovarian cancer model as a prelude to future therapy studies. AdCMVhSSTr2 was produced and used to induce hSSTr2 on A427 human nonsmall cell lung cancer cells and on SKOV3.ipl human ovarian cancer cells in vitro, as demonstrated by competitive binding assays using [125I]-Tyr1-somatostatin and [(111)In]-DTPA-D-Phe1-octreotide. Mice bearing i.p. SKOV3.ip1 tumors administered 1 x 10(9) plaque-forming units of AdCMVhSSTr2 i.p. 5 days after tumor cell inoculation, followed by an i.p. injection of [(111)In]-DTPA-D-Phe1-octreotide 2 days later, showed a range of 15.3-60.4% median injected dose/gram (ID/g) in tumor at 4 h after injection compared with 3.5% ID/g when [125I]-Tyr1-somatostatin was administered and 0.3% ID/g when the negative control peptide [125I]-mIP-bombesin was administered. Mice administered a control adenoviral vector encoding the gastrin-releasing peptide receptor did not have tumor localization of [(111)In]-DTPA-D-Phe1-octreotide (<1.6% ID/g), demonstrating specificity of [(111)In]-DTPA-D-Phe1-octreotide for the AdCMVhSSTr2 induced tumor cells. In another set of experiments, the tumor localization of [(111)In]-DTPA-D-Phe1-octreotide was not different 1, 2, or 4 days after AdCMVhSSTr2 injection (31.8, 37.7, and 40.7% ID/g, respectively; P = 0.88), indicating that multiple injections of radiolabeled peptide can be administered with equivalent uptake over a 4-day period. [(111)In]-DTPA-D-Phe1-octreotide tumor localization in animals administered AdCMVhSSTr2 on consecutive days or 2 days apart was 22.4% ID/g and 53.2% ID/g, respectively (P = 0.009) when [(111)In]-DTPA-D-Phe1-octreotide was given 1 day after the second AdCMVhSSTr2 injection. There was no difference in [(111)In]-DTPA-D-Phe1-octreotide localization after a single AdCMVhSSTr2 injection (40.7% ID/g) or two injections of AdCMVhSSTr2 given 1 (45.9% ID/g) or 2 (53.2% ID/g) days apart, where [(111)In]-DTPA-D-Phe1-octreotide was given in each case 4 days after the first AdCMVhSSTr2 injection (P = 0.65). Therefore, two AdCMVhSSTr2 injections did not increase [(111)In]-DTPA-D-Phe1-octreotide tumor localization compared with one injection, which eliminates concerns about an immune response to a second dose of AdCMVhSSTr2. This will be the basis for a therapeutic protocol with multiple administrations of an octreotide analogue labeled with a therapeutic radioisotope.

Radiosensitization mediated by a transfected anti-erbB-2 single-chain antibody in vitro and in vivo.

PURPOSE: The erbB-2 receptor is overexpressed in several human cancers, including ovarian, prostate, and breast. We have developed plasmid and adenoviral vectors expressing an anti-erbB-2 single chain antibody (sFv), directed to the endoplasmic reticulum (ER) of target cells, that is cytotoxic to tumor cells overexpressing erbB-2 through induction of apoptosis. The anti-erbB-2 sFv also sensitizes erbB-2 overexpressing cells to the cytotoxic effects of cisplatin. On this basis, we hypothesized that human ovarian cancer cells expressing anti-erbB-2 sFv with downregulated erbB-2 product, p185erbB-2, also would be sensitized to ionizing radiation. Therefore, we designed experiments to test the ability of the anti-erbB-2 sFv to radiosensitize human ovarian cancer cells in vitro and in vivo. METHODS AND MATERIALS: To test our hypothesis, we established subcutaneous (s.c.) tumors in the flanks of nude mice with SKOV3.ip1 human ovarian cancer cells and SKOV3 cells stably expressing the ER directed anti-erbB-2 sFv (SKOV3/pGT21). The tumors were treated with 10 Gy 60Co, or received no radiation. We then determined the regression rate, delay in regrowth, and time to tumor doubling of the tumors treated with radiation in the transfected group and controls. In addition, SKOV3.ip1 and SKOV3/pGT21 tumors were dissected from the irradiated animals and assayed for differences in p185erbB-2 expression at 12 weeks after irradiation by immunohistochemistry. Further, in vitro clonogenic survival assays were performed on the parental SKOV3.ip1 and SKOV3/pGT21 cell lines. RESULTS: A statistical analysis of the combined data was done for two in vivo experiments. The analysis of the combined data showed that animals with irradiated tumor SKOV3/pGT21 had a significantly higher regression rate (p = 0.0055), longer delay in regrowth (p = 0.0001) and time to tumor doubling (p = 0.0004), than those animals with tumor SKOV3.ip1 that received radiation. We observed a similar significant effect for the same parameters in the unirradiated tumor SKOV3/pGT21 compared to unirradiated tumor SKOV3.ip1. Immunohistochemical analysis of the SKOV3/pGT21 tumor cells demonstrated focal accumulation of p185erbB-2 in scattered clumps of cells and less p185erbB-2 membrane expression than cells of SKOV3.ip1 tumors. However, SKOV3.ip1 and SKOV3/pGT21 cells had similar in vitro sensitivity to radiation. CONCLUSIONS: These data support the hypothesis that tumors with reduced p185erbB-2 expression mediated by the anti-erbB-2 sFv are rendered more susceptible in vivo to the cytotoxic effects of ionizing radiation than tumors that maintain their normal expression of p185erbB-2. However, a similar effect was not observed with the same tumor cells in vitro. Thus, as has been described by others (1, 2), in vitro and in vivo results do not always correlate. Therefore, appropriate assays to assess clinical relevance need to be determined for each particular system studied.

Performance of new hearing aids using the ANSI S3.22-1976 standard.

One hundred new hearing aids were tested to determine their compliance with ANSI S3.22-1976 specifications. Thirty-four models representing eight manufacturers were included. Estimates of the test equipment's accuracy were utilized as required by the standard to correct the tolerances permitted for the 11 measurements made. Results revealed that 68% of the instruments tested met all specifications, when the accuracy of the test apparatus was accounted for, while 11% fewer hearing aids passed all tests when it was excluded. No greater than a 10% difference was found in the performance of various types of aids, such as automatic gain control, directional, linear, or nondirectional.

The influence of transient distortion on reaction time.

Reaction times to acoustic stimuli (250 and 4000 Hz sine waves) varying in rise-decay time (50, 25, 10, 5.0, and 1.0 msec) were obtained from normal hearing listeners (N = 3). Findings indicate that decreasing rise-decay time systematically distorts the shape of the latency-intensity function. Data from the shortest rise-decay condition suggests that transient distortion may affect a relatively small change in signal detectabiliity across a signal intensity range of 75 dB.

The effect of age in brief-tone audiometry.

The influence of age and sex on temporal intergration as it might be measured clinically was assessed in 50 normal-hearing Ss aged 6--24 yrs. A threshold-tracking paradigm was employed. Age did not systematically influence temporal integration. Variability of integration values among Ss of 6--7 yrs indicates that such children are capable of tracking threshold successfully in a brief-tone paradigm. Significant sex differences in integration slope were obtained across test frequency and age group.

Effects of phase manipulation on speech intelligibility through communication headsets.

A masking level difference (MLD) paradigm was established by rewiring the earphones of a communications headset out-of-phase. Essentially no release from masking could be measured, however, on a crew of listeners in the cabin of light aircraft. The experiment was replicated in the laboratory so that the exact phase of the aircraft noise masker could be controlled. The substantial MLD obtained in this environment led to the conclusion that the noise reaching the ear in the cockpit was of random phase, which almost eliminates the MLD. Therefore, rewiring headsets out-of-phase provides no advantage in intelligibility.

Further interpretation of the threshold of octave masking (TOM) test.

The threshold of octave masking (TOM) test was administered to normal-hearing and sensorineural-impaired listeners at four test frequencies; 500, 1000, 2000 and 4000 Hz. The TOM value was found to be inversely proportional to the degree of hearing loss at the masker frequency. Results indicate that the TOM test is capable of distinguishing subjects with sensorineural involvement from those with normal hearing and of providing a measure of the degree of sensory dysfunction. Examination of the slope of octave masking dysfunction. Examination of the slope of octave masking revealed that once the influence of hearing loss is overcome at higher intensities the sensorineural ear performs essentially the same as the normal ear in a tone-on-tone masking task.

Influence of acoustic reflex on acquisition of temporary threshold shift from short duration noise bursts.

The purpose of this study was to examine the relationship between the acoustic reflex elicited by short duration noise bursts and the resultant temporary threshold shift. Acoustic reflex responses were monitored during the presentation of fatiguing stimuli consisting of interrupted and continuously presented octave noise bands (500--1000 and 1500--3000 Hz) presented at 98 dB sound pressure level. For interrupted stimuli, burst duration was maintained at 100 msec while five different off times ranging from 50 to 450 msec (in 100-msec steps) were used. Exposure duration was varied to equate total energy received in each off-time condition. Noise exposures having shorter off times produced significantly more reflex activity than did exposures with longer off times. Greater impedance changes were elicited by the high band noise than by the low band noise exposure. Although the high band noise tended to produce greater reflex activity it also produced significantly more temporary threshold shift. Differences in the amount of temporary threshold shift produced by the two noise bands could not be attributed to the effects of reflex contraction.

Middle ear muscle activity during speech in stapedectomized and laryngectomized subjects.

Middle ear muscle responses associated with speech production were observed in normal-hearing, stapedectomized, and laryngectomized subjects. Impedance changes associated with speech production were monitored by an electroacoustic impedance bridge simultaneously with vocal output. Results from stapedectomized subjects indicate that the tensor tympani muscle contracts prior to vocalization and is part of the neurological pattern of speech production. Data collected from laryngectomized subjects suggest that the presence of sensory fibers from the larynx is not a prerequisite for middle ear muscle activity during speech production.